- 8 oz. (1-3/4 cups) unbleached all-purpose flour; more as needed
- 2 tsp. baking powder
- 1 tsp. granulated sugar
- 1/2 tsp. baking soda
- 1/2 tsp. table salt
- 3 oz. (6 Tbs.) cold unsalted butter, cut into 1/2-inch pieces
- 3/4 cup cold, well-shaken buttermilk
- In a large, wide bowl, combine the flour, baking powder, sugar, baking soda, and salt. Using a pastry blender or your fingertips, cut in the butter until the mixture resembles coarse meal with some pea-size lumps.
- Using a silicone spatula, stir in the buttermilk just until the flour mixture is moistened. Do not overmix; the dough should just come together, and it will be sticky.
- Transfer the dough to a floured work surface and gently knead 6 to 8 times, dusting lightly with flour if needed to keep it from sticking.
Make Ahead Tips
The flour and butter mixture can be refrigerated in a zip-top freezer bag for up to 1 week, or frozen for up to 1 month. If frozen, thaw at room temperature for 30 minutes before proceeding with the recipe.
- 1/4 cup semolina flour
- Dough from above
- All-purpose flour, for rolling
- 3 to 4 medium ripe tomatoes (1-1/2 lb. total), preferably heirloom, cored and sliced crosswise 1/4 inch thick
- Kosher salt
- 2 oz. coarsely grated Gruyère (about 2/3 cup using the large holes of a box grater)
- 1/3 cup mayonnaise
- 1/4 cup finely chopped mixed fresh herbs, such as parsley, basil, and chives
- 1 tsp. finely chopped fresh oregano or marjoram
- Freshly ground black pepper
- Position a rack in the center of the oven and heat the oven to 425°F.
- Sprinkle a 12×17-inch sheet of parchment with 2 Tbs. of the semolina flour. On the semolina, pat the biscuit dough into a 5-inch round. Using a floured rolling pin, roll the dough into a 13-inch round, lightly dusting with all-purpose flour to keep the dough from sticking, if necessary.
- Transfer the dough on the parchment to a large rimmed baking sheet. Sprinkle the remaining 2 Tbs. semolina flour over the dough, leaving a 1-1/2-inch border.
- Arrange the tomatoes over the dough in two flat, slightly overlapping concentric circles, lightly salting each circle as you go.
- Combine the cheese, mayonnaise, herbs, and 1/8 tsp. pepper in a small bowl. Dollop in generous tablespoons over the tomatoes. Fold the dough border over the edges of the tomatoes, pleating the dough as necessary.
- Bake until the crust is golden-brown and the tomatoes are tender, 20 to 25 minutes. Let cool on a wire rack until warm, about 30 minutes, before cutting into wedges and serving. You can also serve it at room temperature.
