1. Heat oven to 350°F. Line bottom of 13x9x2-inch baking pan with wax paper.
2. Stir together granulated sugar, flour, cocoa, baking powder and baking soda in large bowl. Add milk, egg substitute, oil and vanilla; beat on medium speed of mixer 2 minutes. Add water; stirring with spoon until well blended. Pour batter into prepared pan.
3. Bake 16 to 18 minutes or until wooden pick inserted in center comes out clean. With knife or metal spatula, loosen cake from edges of pan. Place clean, lint-free dish towel on wire rack; sprinkle lightly with powdered sugar. Invert cake on towel; peel off wax paper. Cool completely. Invert cake, right side up, on cutting board. Cut cake into 42 small rectangles (about 2x1-1/4 inches).
4. Stir orange peel into whipped topping; drop spoonful of topping on each piece of cake. Garnish as desired. Store cake, covered, at room temperature. 42 pieces (3 rectangles per serving).