1. Grease and flour a 15x10x1-inch baking pan. In a bowl stir together flour, cocoa powder, baking powder, and salt. Set aside. In a small mixing bowl beat egg yolks and vanilla with an electric mixer on high speed about 5 minutes or until lemon-colored. Gradually add the 1/3 cup granulated sugar, beating on medium speed 5 minutes or until sugar is almost dissolved. Wash beaters.
2. In a large mixing bowl beat egg whites on medium speed until soft peaks form (tips curl). Gradually add the 1/2 cup granulated sugar, beating on high speed until stiff peaks form (tips stand straight). Fold egg yolk mixture into beaten egg whites. Sprinkle flour mixture over egg mixture; fold in gently just until combined. Spread batter evenly into prepared pan.
3. Bake cake in a 375 degree F oven for 12 to 15 minutes or until top springs back when lightly touched. Immediately loosen edges of cake from pan; turn out onto a towel sprinkled with powdered sugar. Roll up towel and cake, starting from one of the short sides. Cool on a wire rack.
4. Unroll cake. Spread softened ice cream on cake to within 1 inch of edges. Roll up cake without towel. Wrap in foil; freeze 4 hours or up to one week.
5. To serve, slice ice cream roll; place slices on dessert plates. Garnish as desired using candy canes, peppermint bark or a chocolate sauce.