The BEST Easy Low-Carb Crustless Tomato Pie [Keto & Gluten-Free] – Perfect for Home Bakers

Have you ever ended up with a watery, soggy crustless tomato pie that just won’t slice? That frustrating moment when your beautiful low-carb creation turns into a puddle is exactly what this recipe is built to prevent.

The secret to a perfect crustless tomato pie is removing excess moisture from the tomatoes. Salt sliced tomatoes, let them sit on paper towels for 20 minutes, then pat dry. Pre-sweating prevents a watery filling and ensures a firm, sliceable pie. This technique works for any low-carb or gluten-free tomato pie.

After making this recipe a dozen times in my own kitchen, I’ve nailed down a foolproof method that delivers a bubbling, cheesy, sliceable pie every time—with only 5g net carbs per serving. Let’s walk through every detail so you can enjoy a perfect low-carb tomato pie without a soggy disaster.

9 Foolproof Steps to the Best Easy Low-Carb Crustless Tomato Pie

1. Choose and Prep the Right Tomatoes for a Non-Soggy Pie

Pin this step to your ‘Keto Recipes’ board to always remember the tomato-sweating trick!

The very first step sets the foundation for a non-soggy pie. Roma or plum tomatoes are your best friends here because they have naturally lower moisture content than beefsteak or heirloom varieties. Slicing them into ¼-inch thick rounds and then sweating them with salt draws out excess water—over a tablespoon per tomato—thanks to the process of osmosis. This simple technique is the non-negotiable secret behind every perfect slice. Don’t skip the 20-minute rest; even 10 minutes helps.

Ingredients:

• 4 large Roma tomatoes (or 5 medium plum tomatoes) – firm, ripe, not overripe
• 1 teaspoon coarse kosher salt (not table salt – it’s too fine and can make the pie salty)
• Paper towels or clean kitchen towel

Instructions:

1. Wash tomatoes, remove stem core, and slice into ¼-inch thick rounds.
2. Arrange slices in a single layer on a double layer of paper towels.
3. Sprinkle both sides lightly with kosher salt.
4. Let rest for 20 minutes. You’ll see beads of water form on the surface.
5. After 20 minutes, place another paper towel on top and press gently to absorb the released moisture.
6. Pat each slice dry with a fresh paper towel. They should feel dry to the touch.

Pro-Tip: Don’t skip the salting step. Even if you’re short on time, 10 minutes makes a noticeable difference. The salt also seasons the tomatoes, so you don’t need extra salt later.

2. Sauté Sweet Onions for a Savory Foundation

Swipe this technique to your ‘Low Carb Sides’ board!

While the tomatoes drain, you can build a savory base with sweet onions. Onions like Vidalia or Walla Walla add a natural sweetness that balances the acidity of the tomatoes without any added sugar. Sautéing them in butter until just golden—about 5 minutes—deepens their flavor and softens their texture so they blend seamlessly into the layers. Avoid over-browning, which can introduce bitterness.

Ingredients:

• 1 medium sweet onion (Vidalia or similar)
• 1 tablespoon butter (unsalted, or coconut oil for dairy-free option)
• Pinch of salt

Instructions:

1. Peel onion and slice into thin half-rings (about ⅛ inch thick).
2. Melt butter in a small skillet over medium heat.
3. Add onion slices and a pinch of salt. Stir to coat.
4. Cook for 5–7 minutes, stirring occasionally, until soft and lightly golden. Do not brown too much or they’ll become bitter.
5. Remove from heat and set aside.

Pro-Tip: If you’re not on a strict keto plan, a teaspoon of brown sugar substitute (like Swerve) can deepen the caramelization – but the onions are sweet enough on their own.

3. Whisk Up the Creamy Egg–Mayo Binding Mixture

Save this creamy binder idea for your next keto bake!

Without a crust, the structural backbone of this low-carb tomato pie comes from a simple egg-and-mayonnaise mixture. The eggs coagulate during baking, creating a custard-like texture that holds the layers together, while the mayonnaise adds richness and helps prevent rubberiness. Full-fat, real mayonnaise works best; low-fat varieties tend to separate in the oven. If you’re looking for a mayo-free alternative, substitute with an equal amount of plain full-fat Greek yogurt plus a tablespoon of olive oil.

Ingredients:

• 3 large eggs
• ½ cup full-fat mayonnaise (or ¼ cup plain Greek yogurt + ¼ cup mayo for lighter version)
• ¼ teaspoon black pepper
• ¼ teaspoon garlic powder (optional)
• ¼ cup grated Parmesan cheese (for extra flavor)

Instructions:

1. Crack eggs into a medium bowl. Whisk until yolks and whites are fully combined.
2. Add mayonnaise, pepper, garlic powder, and Parmesan. Whisk until smooth and creamy.
3. Set aside. The mixture will thicken slightly as it sits – that’s normal.

Pro-Tip: If you’re avoiding eggs, try a flax egg (1 tbsp ground flax + 3 tbsp water per egg, let sit 5 minutes). The texture will be a little less custardy, but still delicious.

4. Layer the Pie Base: Tomatoes, Onions, and Cheese

Pin this layering technique to your ‘Keto Meals’ board for quick reference!

Now it’s time to assemble. The order matters: tomatoes, onions, cheese, repeat. Starting with a tomato layer creates a solid base, and each cheese layer acts like an internal glue that helps the structure hold together when you slice. Pressing a bit of shredded sharp cheddar against the sides of the dish creates a beautiful crispy cheese rim that mimics a crust. Use a 9-inch glass pie dish for even heat distribution.

Ingredients:

• Prepared tomato slices (from step 1)
• Prepared sautéed onions (from step 2)
• 1 cup shredded sharp cheddar cheese (about 4 oz)
• Additional herbs: 2 tbsp fresh basil, chopped

Instructions:

1. Lightly grease a 9-inch glass pie dish with butter or non-stick spray.
2. Arrange half of the tomato slices in a single overlapping layer on the bottom.
3. Scatter half of the sautéed onions evenly over the tomatoes.
4. Sprinkle half of the cheddar cheese on top.
5. Repeat the layers: remaining tomatoes, remaining onions, remaining cheese.
6. Sprinkle fresh basil evenly over the top.

Pro-Tip: For a cheese crust effect, press some extra shredded cheddar around the edges of the dish and up the sides. It bakes into a crispy, cheesy rim that mimics a real crust.

5. Pour the Egg Mixture Evenly Over the Layers

Save this pouring technique – it ensures every bite is perfectly moist!

With the layers in place, the egg mixture needs to reach every crevice. Pour slowly in a spiral starting from the outside edge, then gently poke the layers with a fork a few times to let the liquid settle down. Give the dish a couple of firm taps on the counter to release air bubbles, then let it sit for 5 minutes so the mixture fully absorbs. The filling should reach about three-quarters of the way up the dish—it will puff slightly during baking.

Ingredients:

• Prepared egg-mayo mixture (from step 3)
• Assembled pie layers (from step 4)

Instructions:

1. Slowly pour the egg-mayo mixture over the top of the assembled layers, starting from the edges and working inward.
2. Use a fork to gently poke down through the layers in a few places to help the mixture settle evenly.
3. Tap the dish on the counter a couple times to release any air bubbles.
4. Let it sit for 5 minutes to allow liquid to fully absorb into the layers.

Pro-Tip: If the mixture doesn’t cover the top completely, don’t worry – the cheese on top will brown and the tomatoes will release some juice. The layers will settle during baking.

6. Top with Extra Cheese and Bake at 375°F

Pin this money shot to your ‘Keto Comfort Food’ board – you’ll thank me later!

A final layer of sharp cheddar and Parmesan on top creates that irresistible bubbly cheesy topping through the Maillard reaction. Baking at 375°F on the middle rack is the sweet spot: high enough to set the eggs and brown the cheese without burning the bottom. Place the dish on a baking sheet to catch any drips. After 30–35 minutes, the top should be golden and the center should just barely jiggle. Use a food thermometer to confirm 165°F in the center for food safety.

Ingredients:

• ¼ cup additional shredded sharp cheddar (for topping)
• 1 tablespoon grated Parmesan
• Fresh basil for garnish

Instructions:

1. Preheat oven to 375°F (190°C). Position rack in the middle.
2. Sprinkle remaining ¼ cup cheddar and Parmesan over the top layer.
3. Place pie dish on a baking sheet (to catch any drips).
4. Bake for 30–35 minutes, until the top is golden brown and bubbly, and the center is set (jiggles only slightly when shaken).
5. If the top isn’t browned enough after 30 minutes, switch to broil for 1–2 minutes – watch closely!
6. Remove from oven and let cool on a wire rack for at least 10 minutes before slicing.

Pro-Tip: Use a food thermometer to check the center – it should read 165°F. This ensures the eggs are fully set. Letting it rest is non-negotiable; it finishes cooking and makes slicing possible.

7. Cool, Garnish with Basil, and Slice Cleanly

Save this final presentation to your ‘Summer Dinners’ board!

Patience at this stage transforms a fragile hot pie into picture-perfect wedges. Let the pie rest for at least 10 minutes (up to 20) on a wire rack so the eggs finish setting and the layers firm up. Running a thin spatula around the edge and using a sharp chef’s knife—wiped clean between cuts—gives you the cleanest slices. For truly flawless pieces, cool the pie completely, then refrigerate for 30 minutes before cutting. Garnish with fresh basil and a sprinkle of flaky sea salt.

Ingredients:

• Fresh basil leaves (about 4-5 large leaves)
• Optional: microgreens or edible flowers for garnish

Instructions:

1. After removing from oven, place on wire rack. Let cool for at least 10 minutes (up to 20).
2. Run a thin spatula around the edge to loosen.
3. Use a sharp knife to cut into 8 wedges. Wipe the blade clean between cuts.
4. Garnish each slice with a fresh basil leaf and a sprinkle of flaky sea salt.
5. Serve warm or at room temperature.

Pro-Tip: For cleanest slices, refrigerate the completely cooled pie for 30 minutes before cutting. Cold filling slices like a quiche.

8. Nutritional Breakdown and Keto Macros

Pin this macro-friendly slice to your ‘Keto Meal Prep’ board!

Each serving (one-eighth of the pie) delivers 5g net carbs, making this pie a fantastic addition to any keto or low-carb meal plan. The macros were calculated using Cronometer with standard ingredients (Duke’s mayonnaise, Kraft sharp cheddar, large eggs). Your values may vary if you use different brands, so always weigh ingredients for accuracy. If you substitute Greek yogurt for mayonnaise, the net carbs can drop to 4g per slice.

Instructions:

• Serving size: 1/8 of pie (one wedge)
• Calories: ~130
• Fat: 10g
• Protein: 12g
• Total Carbs: 7g
• Fiber: 2g (from tomatoes and onions)
• Net Carbs: 5g
• Sugar: 3g (naturally occurring)

Pro-Tip: If you omit the Parmesan and use Greek yogurt instead of mayo, you can knock the net carbs down to 4g and reduce calories by about 20 per slice. Perfect for strict keto or low-cal plans.

9. Variations and Substitutions: Customize Your Pie

Save this variations cheat sheet to your ‘Keto Swaps’ board!

One of the best things about this low-carb crustless tomato pie is how easily it adapts to different tastes and dietary needs. I’ve tested every swap below, and each one works beautifully when you follow the same moisture-control principles. The key is to pre-cook any water-rich vegetables (mushrooms, bell peppers) before adding them, and to adjust baking time by 5 minutes if you add extra liquid ingredients.

Ingredients (choose your swap):

• Mayo-free: Use ½ cup full-fat plain Greek yogurt + 1 tbsp olive oil (or just ½ cup yogurt)
• Bacon lovers: Add 4 slices cooked, crumbled bacon to the middle layer
• Cheese swap: Replace cheddar with equal parts mozzarella (stringier) or Gouda (smokier)
• Add protein: Layer ½ cup cooked, crumbled Italian sausage or ground beef
• Vegetarian / extra veggies: Add ½ cup chopped bell peppers or mushrooms (sauté first)
• Herb variation: Substitute basil with 1 tbsp fresh thyme or oregano

Instructions:

1. Follow the main recipe but incorporate the chosen substitution in the appropriate step (e.g., add bacon when layering cheese).
2. Adjust bake time if adding extra wet vegetables (add 5 minutes).

Pro-Tip: Adding raw vegetables without pre-cooking can introduce extra moisture. Sauté mushrooms or peppers first to release water, then drain before adding.

Key Takeaways: Your Quick Guide to Easy Low-Carb Crustless Tomato Pie

• Salt and drain tomatoes thoroughly – this single step transforms a soggy mess into a sliceable, firm pie. Use Roma tomatoes for the lowest moisture content, and pat dry after salting.
• Use a 1:2 ratio of eggs to mayo for the perfect creamy binder that sets without being rubbery. Three large eggs plus ½ cup full-fat mayo is the sweet spot for 8 servings.
• Layer ingredients in the right order – tomatoes, onions, cheese, repeat – to create structure. Each cheese layer acts like glue between the moist tomato slices.
• Bake at 375°F for 30-35 minutes on the middle rack. This temperature ensures the eggs set through without separating, and the cheese turns bubbly golden brown.
• Let the pie cool for at least 10 minutes before slicing. This resting period allows the filling to firm up, making clean cuts possible. For best results, refrigerate 30 minutes before slicing.
• Track your macros accurately – each wedge has 5g net carbs, 130 calories, 10g fat, and 12g protein. Perfect for keto or low-carb meal prep.
• Experiment with swaps freely: substitute Greek yogurt for mayo, add bacon, or change cheeses – but always pre-cook watery vegetables to keep the pie from getting soggy.

People Also Ask About Easy Low-Carb Crustless Tomato Pie

Why is my tomato pie watery?

The most common cause is not removing excess moisture from the tomatoes. Fresh tomatoes are about 95% water. If you skip the step of salting and draining them, that water releases during baking and creates a liquid layer. Always salt sliced tomatoes, let them sit on paper towels for 20 minutes, then pat them completely dry before layering. This simple technique prevents a watery crustless pie every time.

How many carbs in a slice of crustless tomato pie?

One serving (1/8 of the pie) contains approximately 5 grams of net carbs. Total carbs are around 7g, minus 2g of fiber from tomatoes and onions. The egg-mayo binder adds negligible carbs. If you use a lower-carb cheese or Greek yogurt, net carbs can drop to 4g per slice. Always check your specific ingredient brands for exact numbers.

Can I make crustless tomato pie without mayonnaise?

Yes, you can substitute mayonnaise with an equal amount of full-fat plain Greek yogurt or a combination of half yogurt and half sour cream. The pie will be slightly less rich and a bit tangier, but it still sets well. Avoid low-fat dairy – it can separate during baking. For a completely mayo-free version, use ½ cup Greek yogurt plus 1 tablespoon olive oil.

What are the best tomatoes for crustless tomato pie?

Roma or plum tomatoes are ideal because they have the lowest moisture content. They also hold their shape better after baking. Beefsteak tomatoes can be used but require extra draining (up to 30 minutes). Heirloom tomatoes add beautiful color but have higher water content – salt them generously and drain for at least 25 minutes. Avoid cherry or grape tomatoes as they don’t layer well.

How do I keep crustless tomato pie from getting soggy?

The key is a three-step moisture removal process: salt, drain, and pat dry. After slicing, sprinkle tomatoes with salt and let them sit on paper towels for 20-30 minutes. Then gently press another paper towel on top to absorb released liquid. Finally, pat each slice individually with a fresh towel. This removes enough water to prevent a soggy crustless pie.

Can I freeze crustless tomato pie?

Yes, you can freeze the baked pie for up to 3 months. Let it cool completely, then wrap tightly in plastic wrap and aluminum foil. To serve, thaw overnight in the refrigerator and reheat in a 350°F oven for 15-20 minutes until warmed through. Freezing after slicing is easier – wrap individual wedges and reheat as needed.

How to reheat crustless tomato pie?

The best way to reheat is in the oven at 350°F for 10-15 minutes. This keeps the crusty cheese top crisp and the filling firm. Microwave reheating works for speed (1-2 minutes) but the texture becomes softer and the cheese can turn rubbery. For meal prep, reheat from frozen directly in the oven (add 5-10 minutes).

Is crustless tomato pie keto friendly?

Yes, this crustless tomato pie is keto friendly with only 5g net carbs per serving. It contains no grains or sugar, and the high fat content from cheese and mayonnaise keeps it within standard ketogenic macro ratios (70% fat, 25% protein, 5% carbs). It’s also gluten-free, making it suitable for both keto and gluten-sensitive diets.

Can I make crustless tomato pie ahead of time?

Absolutely. You can assemble the entire pie (without baking) up to 24 hours ahead. Cover tightly and refrigerate. When ready to bake, add a few extra minutes to the cooking time (about 5-7 minutes) since the dish is cold. The baked pie also keeps well in the fridge for 4-5 days and can be reheated for quick dinners.

What to serve with southern crustless tomato pie?

This pie pairs beautifully with a crisp green salad or grilled protein. For a classic Southern spread, serve with black-eyed peas, collard greens, or smoked meat. It works as a side dish with BBQ chicken or fish. For a light keto lunch, pair it with a side of avocado slices or bacon-wrapped asparagus.

Final Thoughts on This Easy Low-Carb Crustless Tomato Pie

This crustless tomato pie proves that you don’t need a crust to enjoy the rich, savory flavors of a classic Southern side dish. The secret lies in one simple kitchen technique: salting and draining the tomatoes to remove their excess moisture. Combine that with a creamy egg-mayo binder, layers of sharp cheddar, and perfectly caramelized onions, and you get a pie that slices cleanly, melts in your mouth, and fits perfectly into your low-carb or keto lifestyle.

I’ve made this recipe dozens of times – for family dinners, backyard BBQs, and even holiday brunches – and it never fails to impress. The best part? It comes together in just over 10 minutes of prep, with only 5g net carbs per serving. No soggy bottoms, no watery filling, just pure, comforting tomato pie.

Now I’d love to hear from you. Have you tried a crustless tomato pie before? What’s your favorite cheese to use? Drop a comment below and share your experience – I always enjoy learning new twists on this beloved dish.

Last update on 2026-07-18 at 23:12 / Affiliate links / Images from Amazon Product Advertising API