Apple Crumb Pie

1 pre-baked gluten-free pie crust (see Tasty Pie Crust recipe)
1/4 cup gluten-free all purpose baking flour
1/4 cup almond meal/flour
1/2 cup gluten-free oats
3/4 cups sugar
1 teaspoon cinnamon
1/2 cube butter (use 1/4 cup shortening with 1/8 teaspoon salt for casein-free)
6 green apples, sliced

Combine flours, oats, sugar, and cinnamon to mixing bowl. Cut in butter (or shortening) with a pastry cutter until mix resembles course crumbs. Pour half of the mix over sliced apples and mix together. Put apple mixture in pie crust. Pour remaining mix over the top. Cover crust with foil to prevent burning. Bake at 350 degrees for 45 to 50 minutes.