In a big bowl, mix together all but topping ingredients and dump into pie crust. Try to even it out but don't worry about being pretty, unless that's your thing.
In a smaller bowl, mix together dry ingredients. Cut in butter with a pastry cutter or knives until the mixture resembles coarse crumbs. Sprinkle over the top of the pie.
Place unwrapped pie in freezer for 24 hours, then wrap in foil and place in a ziploc bag.
To bake, preheat oven to 350. Unwrap pie and put it into the oven without thawing. Bake for 50-60 minutes or until edges are bubbly. Let cool completely before eating to let pie innards set.