Place one pie crust in the bottom of a 9-inch pie plate and crimp as desired.
Carefully stir together peaches, blueberries, raspberries, sugar, lemon juice, and cornstarch. Let sit for a couple minutes, then drain and pour into prepared pie plate.
Top the pie by making a lattice (see note) or a double crust pie. If using a double crust pie, be sure to cut holes in the top to vent during baking. OR
Top the pie with a crumble topping.
Place a pie shield around the edge of the pie and place the pie on a cookie sheet.
Bake for 10 minutes at 425° then lower the temperature to 350°F and bake for about 40-50 minutes, or until crust is baked through and golden.
You can use any topping for this pie: make a lattice pie crust, a crumble topping, or make a double crust pie.If using frozen berries, make sure they are thawed and drained well.Be sure to read the blog post for all sorts of fruit pie baking tips.