Mix all ingredients (except pie crust and whipped cream) in pan and let stand 5 minute. Next stir ingredients well to blend together. Turn fire on low and gently stir for 1 minute, then turn heat up to medium and continue to stir until mix comes to full boil and continue stirring 5 minutes. Remove from heat and allow to cool 10-20 minutes.
Poor into unsweetened, pre-cooked pie crust, and refrigerate until pie filling is firm, 2-4 hours. Top with low fat, sugar-free whipped cream.