Summer lunches of French tomato mustard tart have made me a tomato lover. For years I never was much of a tomato fan. With the exception of cooked tomatoes, I usually took a pass. But now with all the new (actually old) heirloom varieties available, my opinion has changed. What once seemed sour and mealy is now varied and interesting. Now in late summer, I cannot grow tired of them. But after countless pastas and Caprese Salads, I seek out other uses. A French Burgundian tart flavored with mustard, rosemary, and the best fresh tomatoes I have fit the bill.

This tart uses a 9″ (23cm) tart shell from the Perfect Tart Shell developed based on my research. This shell is a great improvement, easy to make, tasty and flaky. It is a variation of Dorie Greenspan’s Mustard tart, which in itself is a variation of a typical Burgundian dish. From my research, it seems that most French preparations are fairly spartan with practically only mustard and tomatoes on the shell. I like the addition of the créme Fraiche (or plain creme, if you don’t have crème Fraiche handy) and egg that Ms. Greenspan suggests for more substance.
Notes on Ingredients
Choice of Tomato
This recipe will accommodate any tomato of any size or type. However, it is an excellent opportunity to show off heirloom tomatoes. In the accompanying photos, I used a colorful orange and red variety.
By the way, let’s be frank about something. Tomatoes come in odd sizes and they vary from top to bottom. If you use the whole tomato, it is going to show differences in sizes, as mine does — pictured here. So it is not picture-perfect? So what. It is natural and tasty.
Notes on Technique
Baking the Crust
If you follow the Perfect Tart Dough process, the shell is pretty foolproof. You do need to pay attention to the crust in the pre-baking and not overcook it. Since it will be baked more with the filling, it should be light brown when removed from the oven after the pre-bake.

French Tomato Tart
Show off Your Heirloom Tomatoes
Ingredients
9" Tart Shell
- 360g (3 cups) flour
- 25g (scant 2 tablespoons) sugar
- 7g (1 tablespoon) salt
- 170g (6 ounces or 12 Tablespoons) butter chilled and cut into about ½ inch (1 cm) cubes
- 1 large egg
- 65g (ample ¼ cup) crème fraiche
- 30ml (1 ounce) water
Tomato Filling
- 1 large (or 2 medium) tomatoes
- salt and pepper
- 2 tbsp Grainy Dijon mustard
- 2 tbsp Dijon mustard, (may be labeled Ancient or Country Style)
- 6 tbsp crème fraiche or heavy cream
- 3 large eggs
- 2 rosemary sprigs
Instructions
Tart Shell
To make the dough
- If using a mixer, chill the bowl, and paddle in the freezer for at least 20 minutes.
- Whisk the flour, sugar, and salt together.
- Assemble the mixer and bowl, and add dry ingredients. With the mixer on low, slowly add the cubes of butter. Mix for two or three minutes. The butter should be well cut into the dough. After all the pieces of butter are added, increase the speed slightly. Slivers of butter should remain visible. If some bigger chunks remain, work the bigger pieces of butter into the flour between your fingers.
- Beat the egg in with the creme fraiche and mix into the dough with the mixer still on low. The dough should start binding together. Add water if needed to improve texture.
- Turn out the dough onto a cutting board (or work surface). Using your hands, quickly work the dough together into one ball.
- Roll the dough into a disc. Cover with wrap and refrigerate for at least two hours. If not planning to use immediately wrap it well and it will freeze well for at least two months.
To partially bake the shell
- Center a rack in the oven and preheat to 375°F.
- Roll out the dough on a floured surface or between two pieces of wax paper. The disc shape should start you on the way. Work quickly to keep the dough cold while rolling not stretching. If working on a floured surface turn the dough with a quarter turn frequently to keep it from sticking.
- Place the dough inside the tart pan. Carefully push into corners without stretching. Trim excess dough from the edges and save it for another use. Prick the surface of the dough slightly with a fork to prevent air bubbles. Only 4 or 5 pricks should be needed. Coat the dough with foil or parchment paper. Fill with dried beans or pie weights.
- Bake for about 20 minutes until crust edges are lightly browned. (This assumes there will be approximately 30 minutes more baking after the tart is filled. Adjust as needed.)
Filling
- After pre-baking the tart shell, raise the temperature to 425°F.
- Chop the rosemary leaves. Preserve one tender tip of the rosemary to place in the center of the tart before baking.
- Whisk together the eggs, crème Fraiche, and mustard. At this point, you will need to judge the strength of your mustard -- adding more or less depending on the taste. Additionally, salt, again how much may vary with the mustard. Add pepper as desired.
- Slice the tomatoes into about 1 cm (⅓ to ½ inch) slices.
- Pour the egg/cream mixture into the pre-baked tart, gently spreading over the complete tart. Be careful not to overfill given that the tomato slices are to be added.
- Arrange the tomato slices on top of the egg/cream mixture. Arrange the slice close together with an eye to the aesthetics of the final product, but do not overlap. Salt the tops of the tomatoes. Top with a small tender sprig of rosemary.
- Bake for about 30 minutes until the tart is puffed and lightly browned. Cool for at least 5 minutes before serving.
Notes
Adapted from Dorie Greenspan.
Nutrition Information:
Yield: 4 Serving Size: 1Amount Per Serving: Calories: 533Total Fat: 36gSaturated Fat: 21gTrans Fat: 1gUnsaturated Fat: 13gCholesterol: 278mgSodium: 200mgCarbohydrates: 41gFiber: 3gSugar: 5gProtein: 13g
Calculated Nutrition is estimated.