BEAT sugars, egg substitute, margarine or butter and vanilla with electric mixer at medium speed until well blended; stir in pecan halves. Pour into pastry crust.
BAKE at 400°F for 15 minutes; reduce temperature to 350°F. Bake for 20 to 25 more minutes or until lightly browned and completely puffed across top of pie. Cool completely on wire rack. Garnish as desired.