Double-Crust Berry Free-Form Pie

On a lightly floured piece of parchment, roll out one disk of dough to an 18-inch round. Transfer parchment and dough to a baking sheet and refrigerate until just firm, about 10 minutes. Meanwhile, on another lightly floured piece of parchment, roll out remaining disk of dough to a 15-inch round. Leaving a 1-inch border, punch out squares with a 1-inch square cutter in rows, spaced about 3/4 inch apart, to form a grid. Transfer parchment and dough to another baking sheet and refrigerate 10 minutes.

In a bowl, toss berries with cornstarch, granulated sugar, and lemon juice. Spread mixture evenly over center of 18-inch dough round, leaving a 3 1/2-inch border. Center second dough round on top of berries; brush with egg wash. Fold bottom dough over top, pressing to seal and forming pleats as you go. Brush folded edges with egg wash and sprinkle entire surface with sanding sugar. Freeze until firm, about 30 minutes.

Meanwhile, preheat oven to 375 degrees. Bake pie, rotating once, until golden brown and juices are bubbling in center, about 1 hour, 10 minutes. Let cool on a wire rack at least 1 hour before serving.