This Heirloom Tomato Galette is Summer at its Peak

It’s pretty hard to mess up peak-season heirloom tomatoes. Simply sliced, drizzled with olive oil, sprinkled with salt and pepper, they can be an easy dish on their own. Add a simple embellishment and one or two complementary ingredients and summer tomatoes become the centerpiece for some of our favorite seasonal meals. Like a gilt frame on a beautiful masterpiece, this buttery cornmeal crust encompasses the perfect seasonal partnership—one that marries the colorful mix of sliced heirlooms with a hidden layer of basil-studded corn kernels and nutty-flavored gruyère cheese. Paired with an ice-cold glass of rosé or crisp pinot blanc or pinot grigio, this summertime partnership makes for a memorable summer lunch that’s hard to beat.

Heirloom Tomato Tart

For the crust

• 1½ cups (7½ oz/235 g) all-purpose flour
• ½ cup (2½ oz/75 g) cornmeal
• 1 tsp sugar
• 1¼ tsp salt
• ½ cup (4 oz/125 g) cold unsalted butter, cut into cubes
• ⅓ cup (80 ml) plus 1 tbsp ice water
• 3 tbsp olive oil

For the filling

• 2 lb (1 kg) regular and cherry heirloom tomatoes 
• 1 tbsp olive oil
• 4 green onions, thinly sliced
• 2 cloves garlic, minced
• 1 ear corn, husk and silk removed, and kernels cut
  off the cob 
• 1 tbsp thinly sliced fresh basil, plus basil leaves for garnish
• Salt and freshly ground pepper 
• 2 oz (60 g) Gruyère cheese, shredded
• 2 tbsp grated Parmesan cheese
• 1 large egg yolk whisked with 1 tbsp whole milk

To make the crust, in a food processor, combine the flour, cornmeal, sugar, and salt and pulse briefly to mix. Scatter the butter over the top and pulse just until evenly distributed but large chunks of butter remain visible. In a measuring cup, whisk together the ice water and olive oil. Gradually add the ice-water mixture to the flour mixture, pulsing just until the dough begins to hold together but small chunks of butter are still visible. Turn the dough out onto a piece of plastic wrap and press into a rough 4-by-8-inch (10-by-20-cm) rectangle. Cover with the plastic wrap and refrigerate until well chilled, at least 1 hour or up to 1 day. 

Preheat the oven to 375°F (190°C). 

Core the regular tomatoes and cut crosswise into thick slices about ⅓ inch
(9 mm) thick. Cut cherry tomatoes in half. Place the slices in a single layer on several layers of paper towels, cover with another paper towel, and let drain. 

Meanwhile, in a frying pan, warm the olive oil over medium-low heat. Add the green onions and garlic and cook, stirring occasionally, until softened, about 2 minutes. Add the corn kernels and cook, stirring occasionally, for 30 seconds. Remove from the heat, stir in the basil, and season to taste with salt and pepper. Let cool. 

Place a 15-inch (38-cm) square of parchment paper on a work surface. Transfer the dough to the parchment and roll out into a 9-by-14-inch (23-by-35-cm) rectangle. Slide the parchment with the dough onto a baking sheet. Spread the corn mixture over the dough, leaving a 2-inch (5-cm) uncovered border. Sprinkle the Gruyère and Parmesan evenly over the corn. Arrange the tomato slices in an even layer over the cheeses. Lift the edges of the dough and fold them over the filling, leaving the center uncovered. Brush the edges of the dough with the egg mixture. 

Bake until the crust is golden and the tomato juices are bubbling, 35–40 minutes. Scatter basil leaves over the tart, cut into slices, and serve warm. Serves 4 to 6.