2 pie crusts
4 c frozen mixed berries (2 cups raspberries, 1 cup blueberries, 1 cup blackberries)
1 c sugar
1/3 c cornstarch (I might use 1/2 c next time as it was runny)
1/2 tsp salt
Topping: 1 egg white whisked + 1-2 TB sugar for sprinkle
Preheat oven to 375° F. Place baking sheet in oven while the oven preheats.
In a large bowl place frozen berries, combine berries if not using a bag of frozen mixed berries.
In a smaller bowl, stir together the sugar, cornstarch, and salt. Pour over berries, stirring gently until all berries are covered, then, let sit 10-15 minutes.
Meanwhile, par-bake bottom crust 10 minutes or until light golden, using pie weights to keep crust from puffing up. Pour mixed berries into crust leaving out the extra juice that may have accumulated at the bottom of the bowl. Place top crust on top of berries (lattice crust or solid crust with slits), crimp edges, and brush top crust with egg white and then sprinkle with 1-2 tablespoons of sugar.
Bake 50-55 minutes, remove from oven, and cool 3-4 hours to allow the juices to thicken. Slice and serve with whipped cream or ice cream if desired.