01 - Preheat the oven to 400°F.
02 - In a large bowl, combine sliced peaches, granulated sugar, brown sugar, flour, lemon juice, vanilla extract, cinnamon, and salt. Toss gently until peaches are evenly coated. Set aside.
03 - In another bowl, whisk together flour, sugar, and salt for the crust. Add cold butter cubes and cut them into the flour using a pastry blender or fingertips until the mixture resembles coarse crumbs.
04 - Gradually drizzle in ice water, stirring with a fork, until the dough just comes together. Do not overwork. Turn the dough onto a lightly floured surface and shape into a disk. Wrap in plastic and chill for 15 minutes.
05 - Pour the peach filling into a 9x13-inch baking dish.
06 - Roll out the chilled dough to fit the top of the baking dish (about 1/4 inch thick). Place over the peaches, trimming excess and crimping edges. Cut a few small slits in the crust for steam to escape.
07 - Brush the crust with beaten egg, and sprinkle with coarse sugar if desired.
08 - Bake for 40–45 minutes, or until the crust is golden and the filling is bubbling.
09 - Let cool for at least 15 minutes before serving. Enjoy warm, optionally with vanilla ice cream.