For the Cake
1/3 cup cake flour
1/3 cup unsweetened cocoa powder
2 tablespoons cornstarch
1/2 teaspoon baking soda
1/2 teaspoon baking powder
1/3 teaspoon salt
4 large eggs, separated
1 cup granulated sugar, divided
confectioners' sugar
For the Filling
1 container (8 ounces) frozen whipped topping, thawed
MAKING THE CAKE
Preheat oven to 350°F. Line a 15- x 1 0-inch jelly roll pan with waxed paper. Grease and flour lined pan; tap out excess. In a medium bowl, combine flour; cocoa powder, cornstarch, baking soda, baking powder and salt. Mix well. In a separate bowl, using an electric mixer set on medium speed, beat egg yolks and 1/4 cup sugar until fluffY.
In a 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 a toothpick inserted in center comes out clean, about 15 minutes.
ROLLING AND FILLING THE CAKE
Dust a clean cloth with remaining sugar. Turn cake out onto prepared cloth; remove waxed paper. Trim the cake's edges.
Starting with a long side, tightly roll up cake with cloth. Transfer cake, seam¬side down, to a wire rack tq 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.