Set oven to 400°F (200°C).
Roll out one crust into a 9-inch pie plate.
In a large bowl, toss peaches with sugar, cornstarch, lemon juice, and spices.
Pour filling into crust and dot with butter.
Roll out second crust and place on top (or cut strips for a lattice). Seal edges.
Brush with beaten egg for shine.
Bake at 400°F for 20 minutes. Lower to 350°F (175°C) and bake another 30–35 minutes, until filling is bubbly and crust golden.
Cool at least 2 hours before slicing to allow filling to set. Serve with whipped cream or ice cream.