Bake at 425°F for 15 minutes. Keep an eye on your crumble and tent the top with a small piece of foil if the sugar begins to burn. Turn heat down to 350°F and bake for 45-55 minutes. Cover the top of the pie with foil if at any time it begins to brown too quickly. The pie is done when you can insert a knife into the center and feel that the apples are cooked through.