Mix 1 cup flour, margarine and powdered sugar. Press in ungreased baking pan, 8x8", or 9x9", building 1/2 up sides. Bake 20 minutes.
Beat remaining ingredients until light and fluffy, about 3 minutes; pour over the baked layer.
Bake until no indentation remains when touched in the center, about 25 minutes. Cool. Sprinkle with more powdered sugar if desired. Cut into squares.
Razzle Dazzle Recipes