01 - Preheat oven to 400°F.
02 - Combine sliced peaches, granulated sugar, brown sugar, flour, lemon juice, vanilla, cinnamon, and salt in a large bowl. Toss gently until peaches are evenly coated. Set aside.
03 - Whisk together flour, sugar, and salt for the crust in a separate bowl.
04 - Add cold butter cubes to the flour mixture. Cut into flour using a pastry blender or fingertips until mixture resembles coarse crumbs.
05 - Gradually drizzle in ice water while stirring with a fork until dough just comes together. Avoid overworking the dough.
06 - Turn dough onto a lightly floured surface and shape into a disk. Wrap in plastic and refrigerate for 15 minutes.
07 - Pour the peach filling into a 9x13-inch baking dish.
08 - Roll the chilled dough to fit the top of the baking dish, approximately 1/4 inch thick. Place over peaches, trim excess, and crimp edges. Cut small slits in crust for steam to 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 bubbly.
11 - Let cool for at least 15 minutes before serving. Best enjoyed warm, optionally with vanilla ice cream.