10 cups blackberries
2 cups of sugar
1/4 cup flour or tapioca
1 tsp almond or vanilla extract
1/2 cup butter, melted
Pastry for double crust pie
Preheat oven to 375 degrees F.
Combine berries, sugar, and flour in a large heavy pot. Allow to set until sugar is dissolved and syrup forms. Over medium low heat, bring the berries mixture to a boil, then reduce heat to low and cook about 10 minutes. Remove from heat and stir in butter and extract. Set aside and keep warm. Put half of the berries into buttered 9×13 baking dish.
Roll out half the pasty and cut to 9×13 and place over berries in baking dish. Bake for until pastry is lightly browned. Remove from oven and spoon remaining berriy mixture over the baked pastry.
Roll out the remaining pasty and cut into strips about an inch wide. .Arrange strips in a loose lattice weave over the berry mixture. Sprinkle lightly with sugar. Bake until lightly browned and berries bubble up through the lattice.