Roll pastry on floured surface into circle 1 1/2 inches larger than inverted 9-inch pie pan. Ease pastry into pan; trim and flute.
Mix sweet potatoes, eggs, margarine, sugar substitute, and flour until blended in large bowl; mix in remaining ingredients, except whipped topping. Pour mixture into pastry.
Bake at 425 degrees F for 20 minutes; reduce heat to 350 degrees F and bake until filling is set and sharp knife inserted halfway between center and edge comes out clean, 30 to 35 minutes. Cool on wire rack. Serve with light whipped topping.
Variation: Spiced Pumpkin Pie-Make recipe as above, substituting canned pumpkin for the sweet potatoes and omitting eggs, margarine, flour, vanilla, and mace.
163 calories, 3 grams fat, 27 grams carbohydrates, 6 grams proteinper serving. This recipe is low in fat.