Place egg whites in large bowl; let stand at room temperature for 30 minutes. Line a greased 15-in. x 10-in. x 1-in. baking pan with waxed paper; grease the paper and set aside.
In a large bowl, beat egg yolks on high speed for 5 minutes or until thick and lemon-colored. Gradually beat in 1/2 cup sugar. Sift the flour, cocoa, baking powder and salt together twice; gradually add to yolk mixture and mix well (batter will be very thick).
In a large bowl with clean beaters, beat egg whites on medium speed until soft peaks form. Gradually beat in remaining sugar, 1 tablespoon at a time, on high until stiff peaks form. Gradually fold into batter. Spread evenly into prepared pan.
Bake at 375° for 10-12 minutes or until cake springs back when lightly touched. Cool for 5 minutes. Invert cake onto a kitchen towel dusted with confectioners' sugar. Gently peel off paper. Roll up cake in towel jelly-roll style, starting with a short side. Cool on a wire rack.
Unroll cake; spread jam to within 1/2 in. of edges. Top with ice cream. Roll up without towel. Place seam side down on a platter. Cover and freeze for at least 4 hours before slicing. May be frozen for up to 2 months. Sprinkle with confectioners' sugar; serve with hot fudge topping and whipped topping. Yield: 12 servings.