You’re going to love this AMAZING Heirloom Tomato Tart. Gruyere cheese, fresh basil and herbs and a flaky crust topped with sliced heirloom tomatoes combine for an impressive appetizer.

I’m loving the fresh tomatoes that are everywhere this summer. Taylor is a big tomato pie fan so I’ve been experimenting this summer with tomato pie and tomato galette both of which make a great vegetarian meal. This heirloom tomato tart recipe, is lighter and not quite so filling and works great for an appetizer.
The crust is easy to work with and while flaky, is still sturdy enough to hold the toppings. The eggs added to the dough give it a nice color and texture. What was so surprising to me was that when I re-heated it the following day, it was just as flaky.
Two days later, it was starting to get a little soft, but still held its shape. You won’t need to worry about it getting soggy as it cools.
This makes a large tart, enough for a cocktail party. You can make the crust ahead of time and then add the toppings before you’re ready to bake. I love having an appetizer that is delicious at room temperature and doesn’t get soggy by the end of the night.
BAKING TIP: Adding a similar sized baking sheet to the top of the crust while baking will keep it from shrinking just like pie weights will do.
A coating of mustard over the baked crust is unexpected but pulls all the flavors together, like it does in this apricot chicken recipe, and I’m not even a big mustard fan.
Why you’ll love this tomato appetizer
- This tart serves a lot of people, so great for parties.
- Fresh tomatoes and a buttery crust, how can you go wrong.
- Fresh herbs and tomatoes with dijon mustard over cheese makes an impressive dish.
- A flaky crust holds all the summer flavors together perfectly!
How to store tomatoes for the best flavor
You want to try to use the freshest tomatoes for a tomato tart but do you know how to store your tomatoes so they have the best flavor and aren’t mushy? Here are a couple of tips:
- For unripe tomatoes, don’t store them in the refrigerator. The cold temperature will keep the flavor from developing and it will turn the texture mushy. Let them sit on the counter to ripen.
- Ripe tomatoes, store on the counter. However, once ripe, if you’re not ready to eat them, place them in the refrigerator for a couple of days to stop the ripening and then bring them out a day or so before you are ready to eat them. Since they’re already ripened before refrigerated the coldness will not affect the flavor.
- Overripe tomatoes, you have to refrigerate but they will not be affected by the cold temperature.
What you’ll need
- Tomatoes – they should be ripe but not over ripe. I like to use heirloom tomatoes or mix it up and use yellow and red.
- Fresh herbs – basil and thyme. If you don’t have fresh herbs, you could use pesto instead, just reduce the garlic.
- Cheese – gruyere adds a mild flavor.
- Mustard – this is the surprise ingredient that makes this an over the top appetizer.
How to make an heirloom tomato tart
Step 1:
Make the crust first since it needs to refrigerate for 30 minutes. It’s a basic pie crust but with egg yolks. Once refrigerated, bake and let it cool.
Step 2:
With fresh tomatoes in hand, slice and marinate them in a basil, garlic pesto while the crust is cooling.
Step 3:
Once cooled, top the crust with a whole grain mustard. I’m not a big mustard fan but this just gives it a hint of mustard flavor and is not overwhelming. It could be because you cover the mustard with cheese.
Step 4:
Drain the tomatoes really well and place them on the crust and then top with more cheese. I used heirloom tomatoes which are a bit sweeter but are not even or uniform at all. It still looks gorgeous whether your tomatoes are pretty or not and I always get lots of oohs and ahhs from friends and family.
We absolutely love an heirloom tomato tart. It’s great warm or at room temperature, so perfect if you’re having friends over for an appetizer or to munch on while sitting outside with your favorite beverage.
FAQs and tips
Place a similar sized baking sheet on top of the crust while baking.
Make sure you drain the tomatoes before placing on the crust.
This will still stay fresh for about a day, after that it gets soggy. Re-heat in a 350º oven for 5-10 minutes.
Puff pastry is not a good substitute for a tomato tart because the tomatoes are too juicy and it won’t be strong enough to hold the topping. You could use a regular pie crust instead of this one that has eggs in it.
Any type of tomato will work for this tart, the riper the better.
MORE summer tomato dishes!
Adapted from Ina Garten’s Cooking for Jeffrey
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Heirloom Tomato Tart
Ingredients
CRUST
- 2 ½ cups flour
- 1 teaspoon salt
- 12 tablespoons butter cold and cut into 1 inch pieces
- 2 egg yolks
- ½ cup ice water
TOPPING
- 2 ½ lbs tomatoes about 3-4
- ½ cup fresh basil packed
- 3 cloves garlic
- 1 tablespoon fresh thyme
- salt and pepper
- ½ cup olive oil
- 4 tablespoons dijon mustard
- 12 ounces gruyere grated
- ½ cup parmesan cheese grated
Instructions
CRUST:
- In a food processor, combine flour and salt. Add cold butter and pulse until the size of peas, about 12 times. Add egg yolks and pulse to combine. With the motor running add the ice water and pulse until dough starts to come together. Place on floured surface and roll into a flat disc. Wrap in plastic and refrigerate for 30 minutes.
- Preheat oven to 400º and line a baking sheet with parchment paper.
- Roll out the dough on a floured surface into an 11 x 17 rectangle and place on the prepared pan. Place a second cookie sheet over the dough to weigh it down while baking. Bake for 15 minutes, remove the top cookie sheet and pierce the dough with a fork. Return it to the oven without the top cookie sheet and bake an additional 8-10 minutes until lightly browned.
TOMATOES:
- While the dough is baking prepare the tomatoes. Slice the tomatoes into ¼ slices and place in a large bowl. In the food processor add basil, thyme, garlic, 1 teaspoon salt and 1 teaspoon pepper and process until finely chopped. Add olive oil and process until combined. Pour over sliced tomatoes and gently toss. Set aside while the dough is baking.
- Once the dough has cooled, brush mustard on top and then add ¾ of the gruyere and parmesan. Place sliced tomatoes slightly overlapping on the cheese. Drain the fluid from the tomatoes through a colander and place the herbs and garlic over the tomatoes. Top with remains gruyere.
- Bake at 375º for 30 minutes or until cheese is slightly browned. Cool slightly before cutting into squares.
Barbara’s Tips + Notes
- If you don’t have fresh herbs, use pesto and eliminate the garlic.
- If you’re in a hurry, you can put the crust in the freezer for 15 minutes.
- You can make the crust a day in advance.
- Make sure you drain the tomatoes well before adding
- Slice the heirloom tomatoes thin and overlap the slices
How would i switch f frozen puff pastry for your pastry?
You should be able to use puff pastry, you might have to adjust the baking time.
Beautiful tart!! I love the vine ripened tomatoes of summer. Thanks for sharing at the what’s for dinner party. Hope your week is wildly wonderful!
I’m ready for this beautiful tart with all the tomatoes that will be available in a few weeks! Does the Dijon go in the food processor with the spices, herbs and oilive oil? didn’t seen in the directions where the mustard is mentioned. Thanks for the recipe and very beautiful photos!
Thanks I love to photograph tomatoes! The mustard is spread on the crust after it has baked. Hope you enjoy.