Preheat oven to 325 degrees F.
Place all crust ingredients in a medium bowl.
Cut butter and egg into flour, cinnamon and sweetener with a pastry/dough cutter until mixture resembles small pebbles and the flour is thoroughly moistened.
Press crust mixture into a 9 or 10" pie dish or 2 smaller 6" pie dishes or tart pans.
Bake for approximately 8 to 10 minutes; remove from oven and set aside.Increase oven temperature to 375 degrees F.
In a medium bowl, mix all filling ingredients well until smooth and well blended.
Pour filling into pie dish or pan.
Bake at 375 degrees for 15 minutes; reduce heat to 350 degrees and bake an additional 15 minutes; reduce heat one more time to 325 degrees and bake an additional 20 to 30 minutes, or until knife inserted near center comes out clean.
Cool approximately 2 hours; serve at room temperature after 2 hours or refrigerate.
Serve topped with whipped cream or vanilla ice cream, if desired.