Combine all ingredients and beat until smooth. Pour into a 9-inch pie pan sprayed with cooking spray. Bake at 400 degrees for 15 minutes; reduce temperature to 325 and bake for an additional 45 minutes. Pie is done when the knife comes out clean.
(90 calories per 5-ounce piece or 1/8 of the pie. Add 2 tablespoons of whipped topping for an additional 50 calories if you so desire.)