Heirloom Tomato Galette
2 cups all-purpose flour, plus more for dusting
1 ¼ tsp. kosher salt
12 Tbsp (1½ sticks) unsalted butter, cut into ½” pieces and chilled
1 Tbsp. apple cider vinegar
¼ C ice water, more as needed
1½ lb. ripe heirloom tomatoes, sliced ¼" thick
1 tsp. kosher salt
2 garlic cloves, minced fine or pressed through a garlic press
2 Tbsp extra virgin olive oil
4 oz. mozzarella cheese, shredded (about 1 C – fontina also works well)
1/3 C grated Parmesan Reggiano
2 oz crumbled goat cheese (optional)
1 large egg, beaten
Flaky sea salt & freshly ground black pepper (or red pepper flakes for a little spice) to taste
1 Tbsp. finely chopped chives or fresh basil chiffonade
Make the dough:
Place the flour and 1¼ tsp. kosher salt into the work bowl of your food processor and pulse to combine. Add butter and pulse until mixture resembles coarse meal with a few pea-size pieces of butter remaining.
Transfer mixture to a large bowl; drizzle with vinegar and ¼ cup ice cold water. Toss with a fork to moisten the flour, adding more ice water by the tablespoonful as needed, just until a shaggy dough comes together. Turn out onto a work surface and use a bench scraper to lightly knead, by folding the dough onto itself and pressing down, until no dry spots remain (be careful not to overwork the pastry!). Shape the dough into a disk, wrap in plastic wrap and chill at least 2 hours (may be made up to 2 days ahead).
Assemble the galette:
Preheat oven to 425°. Arrange the sliced tomatoes onto a triple layer of paper towels and sprinkle with 1 tsp kosher salt. Allow the tomatoes to drain for 30 minutes (this helps to prevent a soggy crust). Combine the garlic and extra virgin olive oil. After 30 minutes, press on the tomatoes with additional paper towels to remove excess moisture.
Unwrap dough and roll out on a lightly floured sheet of parchment paper to a 14" round about ⅛" thick. Sprinkle all but 1 Tbsp of the parmesan evenly over the dough and lightly roll to press it into the dough. Transfer on parchment to a baking sheet. Scatter mozzarella cheese over dough, leaving a 1½" border. Arrange tomatoes and over cheese, shingling them slightly then drizzle the garlic oil evenly over the tomatoes. Bring edges of dough up and over filling, overlapping as needed to create about a 1½" border then brush dough with egg and sprinkle with the reserved parmesan. Sprinkle tomatoes with sea salt and pepper to taste. Chill in freezer 10 minutes.
Bake galette, rotating once, until crust is golden brown and cooked through, 55–65 minutes. If using the crumbled goat cheese, add it after the galette has baked for 45 minutes, then finish baking 10-20 minutes longer. Let cool slightly on baking sheet. Sprinkle with the fresh basil chiffonade or chives and serve immediately.