Preheat oven to 375f
Peel and cut apples into quarter sized pieces
In a mixing bowl mix all the dry ingredients together excluding cornstarch
Add the melted butter to the mixture and mix with a fork until evenly distributed
In another bowl mix the sliced apples with cornstarch so they are evenly coated
Add 3/4 cup of crumble mixture to the apples and mix
Pour the apple mixture into the frozen pie crust
Add the crumble to the top to covert apples
Place pie on a cookie sheet covered with tin foil
Cook at 375f for 45-50 minutes or until topping is golden brown
Allow to cool before eating