Chocolate Cake Roll

1/3 C cake flour
1/3 C unsweetened cocoa powder
2 Tbsp cornstarch
1/2 tsp baking soda
1/2 tsp baking powder
1/3 tsp salt
4 large eggs, separated
1 C granulated sugar, divided
confectioners' sugar
1 (8oz) container frozen whipped topping, thawed

Preheat oven to 350. Line a 15x10" jelly roll pan with waxed paper. Grease and flour lined pan; tap out excess. In medium bowl, combine flour, cocoa powder, cornstarch, baking soda, baking powder and salt. Mix well. In separate bowl, using and electric mixer set on medium, beat egg yolks and 1/4 cup sugar until fluffy. In small bowl, using clean beaters, beat egg whites on high until foamy. Gradually add 1/2 cup sugar, beating until stiff, but not dry, peaks form. Fold 1/3 beaten egg whites into egg yolk mixture. Alternately fold in remaining whites and flour mixture. Pour batter in pan; smooth top. Bake until toothpick inserted in center comes out clean, about 15 minutes. Dust a clean cloth with remaining sugar. Turn cake out onto prepared cloth; remove waxed paper. Trim the cakes edges. Starting with a long side, tightly roll up cake with cloth. Transfer cake, seam side down, to wire rack to cool. Unroll cake; remove cloth. Spread whipped topping over cake to within 1/2 inch of edges. Re-roll cake; place seam-side down on a plate. Dust with confectioners' sugar before serving.