- Preheat oven to 425°F.
Prepare crusts for 2 crust pie in a 9-inch pie plate.
- Stir cornstarch and sugar together in a small bowl.
- Place the raspberries and peaches in a large bowl. Add lemon juice and vanilla, then sprinkle sugar mixture over the fruit and toss to coat. Spread in prepared pie plate.
- Carefully lay the top crust over the top of the filling. Crimp and trim the edges as desired. Cut slits to allow steam to escape during baking. Brush pie with egg wash and sprinkle with sanding sugar.
- Place pie pan on a rimmed baking sheet and cover the edges with a pie crust shield. Bake at 425°F for 10 minutes, then lower oven temperature to 350°F and bake until crust is light golden, about 45-55 additional minutes. Cool completely before slicing.
- Store pie in refrigerator for up to 3 days or freeze for up to 3 months.