Peach and Blackberry Crostatas

FOR THE DOUGH
1 ½ cups all-purpose flour
1 tablespoon granulated sugar
½ teaspoon kosher salt
1 stick (4 ounces) unsalted butter, frozen and cut into small pieces
1 tablespoon apple cider vinegar
¼ cup ice water
1 large egg, beaten, for egg wash
Turbinado sugar, for sprinkling

FOR THE FILLING
3 tablespoons granulated sugar
½ teaspoon fresh thyme leaves
3 ripe but firm peaches, halved,
pitted, and cut into ½ inch wedges

6 ounces fresh blackberries
⅛ teaspoon kosher salt
1 teaspoon lemon zest
1 tablespoon fresh lemon juice
½ teaspoon vanilla extract
2 teaspoons all-purpose flour

Make the dough:
Place the four, sugar, and salt in the bowl of a food processor and pulse to combine. Add the butter and pulse until the butter is in pea-size pieces. In a small bowl, combine the vinegar and ice water. Slowly pour the vinegar water into the food processor, pulsing to combine. Pulse just until the dough begins to hold together. Transfer it to a clean work surface and pat together. Shape the dough into a round and cut it into four equal pieces. Wrap each piece in plastic wrap and refrigerate them for at least 1 hour and up to 2 days. 

Preheat the oven to 375ºF. In a small bowl, rub the sugar and thyme together with your fingers to release the herbʼs oils. Place the peaches and blackberries in a medium bowl. Sprinkle the thyme sugar, salt, lemon zest and juice, vanilla extract, and four over the fruit. Toss to coat.
Roll each piece of dough into a ¼-inch-thick round and transfer it to a parchment-lined baking sheet. Divide the fruit evenly between the circles, mounding it into the center of the dough and leaving a 1½-inch (4-cm) border all around. Fold the edges up around the filling. Brush the edges of the dough with the egg wash and sprinkle them with the turbinado sugar. Bake until the crust is golden brown and the fruit is bubbling, 30 to 35 minutes