ArcaMax

1 large egg, lightly beaten

1 tablespoon chopped fresh basil

1. Process flour and 1/2 teaspoon salt in a food processor until combined, about 3 seconds. Scatter butter over the top and pulse until mixture resembles coarse crumbs, about 10 pulses. Transfer to a large bowl. Sprinkle 6 tablespoons of ice water over the flour mixture. Using a rubber spatula, stir and press the dough until it sticks together, adding up to 1 tablespoon more of ice water if the dough doesn’t come together.

2. Turn out the dough onto a lightly floured counter, form into a 4-inch disk, wrap tightly in plastic wrap, and refrigerate for 1 hour. (Wrapped dough can be refrigerated for up to two days or frozen for up to one month.)

3. Toss tomatoes and 1 teaspoon salt together in a second large bowl. Transfer tomatoes to a colander and set the colander in sink. Let tomatoes drain for 30 minutes.

4. Adjust the oven rack to the lower-middle position and heat oven to 375 F. Line a rimmed baking sheet with parchment paper. Let the chilled dough sit on the counter to soften slightly, about 10 minutes, before rolling. Roll the dough into a 12-inch circle on a lightly floured counter, then transfer to prepared sheet (dough may run up lip of sheet slightly; this is OK).

5. Shake the colander well to rid tomatoes of excess juice. Combine tomatoes, shallot, oil, thyme, garlic, pepper and remaining 1/2 teaspoon salt in now-empty bowl. Spread mustard over the dough, leaving 1 1/2-inch border. Sprinkle Gruyere in even layer over mustard. Shingle the tomatoes and shallot on top of Gruyere in concentric circles, keeping within 1 1/2-inch border. Sprinkle Parmesan over the tomato mixture.

6. Carefully grasp one edge of dough and fold up about 1 inch over filling. Repeat around the circumference of the tart, overlapping dough every 2 inches, gently pinching pleated the dough to secure. Brush folded dough with egg (you won’t need it all).

7. Bake until the crust is golden brown and the tomatoes are bubbling, 45 to 50 minutes. Transfer the sheet to a wire rack and let galette cool for 10 minutes. Using a metal spatula, loosen the galette from the parchment and carefully slide it onto wire rack; let cool until just warm, about 20 minutes. Sprinkle with basil. Cut into wedges and serve.

Note: Sharp cheddar cheese can be used in place of the Gruyere, if desired.

(For 25 years, confident cooks in the know have relied on America’s Test Kitchen for rigorously tested recipes developed by professional test cooks and vetted by 60,000 at-home recipe testers. See more online at www.americastestkitchen.com/TCA.)