Heirloom Tomato & Gruyere Tart
Blind-bake an all-butter crust and brush it with Dijon before the tomatoes ever touch it — that mustard layer is a moisture barrier that keeps the pastry crisp beneath juicy heirlooms. Marinate the tomato slices in a bright herb oil, layer them over Gruyère, and bake into a tart that tastes like the very height of summer.
For a few short weeks each summer, heirloom tomatoes arrive in their impossible colors — deep purples, streaked golds, ribboned reds — and a good cook builds a dish to hold them at their peak. This tart is that dish: a buttery crust, a bed of nutty Gruyère, and overlapping slices of marinated heirlooms baked until the cheese bubbles. It is the taste of the season, framed in pastry.
The All-Butter Crust and the Blind Bake
A tart is only as good as its base, and this one is all butter. Pulse cold, cubed butter into the flour just until it forms pea-sized crumbs, bind it with egg yolks and ice water, and chill the disk to relax the gluten and firm the fat — the two things that guarantee a flaky, tender crust. Then blind-bake it with foil and weights until golden and set, so the pastry is already crisp before a single tomato goes on.
The Dijon Moisture Barrier
Tomatoes are gloriously juicy, which is a problem for pastry — and the fix is a thin brush of Dijon mustard across the cooled, blind-baked crust. The mustard forms a protective, flavorful barrier that keeps the tomato juices from soaking in and turning the base soggy, while a scatter of Gruyère beneath the fruit adds another seal. Arrange the herb-marinated slices tightly, top with more Gruyère and Parmesan, and bake until molten and golden.
Heirloom Tomato & Gruyere Tart
Ingredients
Method
- Place the all-purpose flour and ¼ teaspoon of kosher salt into the bowl of a food processor. Add the cold, cubed unsalted butter and pulse until the mixture resembles coarse, pea-sized crumbs.
- Add the egg yolks and pulse to combine. Gradually stream in the ice-cold water, pulsing just until the dough begins to come together.
- Turn the dough out onto a lightly floured marble surface. Pat it gently into a flat disk, wrap tightly in plastic wrap, and chill in the refrigerator for at least 30 minutes to relax the gluten and solidify the butter.
- While the dough chills, arrange the ¼-inch heirloom tomato slices on a large platter or in a shallow bowl in a single layer.
- In a clean food processor bowl, combine the fresh parsley, basil, dill, and garlic cloves. Pulse until finely chopped. Season with ½ teaspoon kosher salt and the coarse black pepper.
- With the machine running, slowly pour in the olive oil to create a thick, bright green herb sauce. Spread this mixture evenly over the resting tomato slices to marinate.
- Preheat the oven to 400°F. Remove the chilled dough from the refrigerator and roll it out between two sheets of plastic wrap (or on a floured surface) to a ¼-inch thickness.
- Transfer the dough to a baking sheet or a fluted tart pan, folding and crimping the edges to form a rustic crust.
- Spray a sheet of aluminum foil with vegetable oil, place it oil-side down over the dough, and fill it heavily with pie weights or dried beans. Bake for 15 minutes.
- Carefully remove the foil and weights, and bake until the crust is golden brown and fully set, about 8 to 10 minutes more. (If the pastry bubbles, pierce gently with a fork). Remove and cool to room temperature.
- Reduce the oven temperature to 375°F.
- Brush the Dijon mustard evenly across the bottom of the cooled, blind-baked crust. (This acts as a critical protective barrier against the moisture of the tomatoes).
- Scatter exactly half of the grated Gruyere cheese directly over the mustard layer.
- Neatly arrange the marinated heirloom tomato slices in a tight, overlapping pattern over the cheese. Top the tomatoes evenly with the remaining Gruyere and all of the grated Parmesan cheese.
- Return the tart to the oven and bake until the cheese is completely melted, bubbling, and deeply golden, about 20 to 30 minutes. Allow to set briefly before slicing. Serve warm or at room temperature.
The Heart of the Table
To serve this tart is to serve the summer itself, caught at the one moment the tomatoes are perfect. There is a deep, seasonal generosity in that — in taking the fleeting best of the garden and turning it into something beautiful enough to set at the center of a table. It is the kind of dish that makes a warm evening feel like an occasion worth remembering.
The Art of the Host
A food processor earns its keep twice here — once for cutting the butter into the crust, and again for whirling the herb oil that marinates the tomatoes. A fluted tart pan gives the cleanest edge, though a rustic free-form crust on a baking sheet is just as lovely. Keep pie weights or dried beans on hand for the blind bake; they're what keep the pastry flat and even.
Neighborly Grace
- The Preparation: Blind-bake the all-butter crust and brush it with Dijon before the tomatoes touch it — that mustard layer keeps the pastry crisp beneath the juicy heirlooms. Marinate the tomato slices in herb oil and drain them well so the tart never goes soggy.
- The Pour: A crisp rosé or a Sauvignon Blanc suits a summer tart. For a non-alcoholic option, a cucumber-basil cooler or a sparkling lemonade keeps it garden-fresh.
- The Vibe: This is high summer on a plate — layered, jewel-toned, and rustic-elegant, best served just warm or at room temperature on a slow afternoon.