01 - Preheat 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 a separate bowl, whisk together flour, sugar, and salt for the crust.
04 - Add cold butter cubes and cut into the flour using a pastry blender or fingertips until mixture resembles coarse crumbs.
05 - Gradually drizzle in ice water, stirring with a fork, until dough just comes together. Do not overwork.
06 - Turn dough onto a lightly floured surface, shape into a disk, wrap in plastic, and refrigerate for 15 minutes.
07 - Pour peach filling into a 9x13-inch baking dish.
08 - Roll chilled dough to fit top of baking dish, about 1/4 inch thick. Place over peaches, trim excess, and crimp edges. Cut small slits in crust for steam escape.
09 - Brush crust with beaten egg and sprinkle with coarse sugar if desired.
10 - Bake for 40-45 minutes until crust is golden and filling is bubbling.
11 - Let cool for at least 15 minutes before serving. Enjoy warm, optionally with vanilla ice cream.