01 - Preheat oven to 400°F.
02 - In large bowl, combine sliced peaches, granulated sugar, brown sugar, flour, lemon juice, vanilla, cinnamon, and salt. Toss until peaches are evenly coated.
03 - In separate bowl, whisk together flour, sugar, and salt. Add cold butter cubes and cut into flour using pastry blender or fingertips until mixture resembles coarse crumbs.
04 - Drizzle in ice water gradually, stirring with fork until dough just comes together. Do not overwork.
05 - Turn dough onto lightly floured surface and shape into disk. Wrap in plastic and refrigerate for 15 minutes.
06 - Pour peach filling into 9x13-inch baking dish.
07 - 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.
08 - Brush crust with beaten egg and sprinkle with coarse sugar if using.
09 - Bake for 40–45 minutes until crust is golden and filling is bubbling.
10 - Let cool for at least 15 minutes before serving. Best enjoyed warm with vanilla ice cream.