Without taking the pie out of the oven, decrease the temperature to 350 degrees and bake for an additional 40-50 minutes.
Cover edges of the pie crust with strips of aluminum foil if necessary to prevent burning.
Check for doneness by inserting a butter knife into the center of the pie. The pie is done when the knife comes out clean. (This will leave a cut in the middle of the pie, which is good. If you don't make a cut in the pie, the surface will crack as it cools.)