Preheat the oven to 400 degrees. Fill the unbaked crust with apples.
Combine 1/2 cup sugar and cinnamon in a small bowl and sprinkle on top of apples slices in pie shell.
Cut butter into the remaining 1/2 cup sugar and flour, which have been mixed together until coarse crumbs form. Sprinkle on top of pie. Bake 40-45 minutes, or until apples are tender when pierced with a fork.