In large mixing bowl, beat eggs at high speed until very light and frothy, about 5 minutes. Gradually beat in confectioners' sugar and beat until very fluffy and lemon-colored, about 5 minutes. Fold cocoa mixture and vanilla into egg mixture until well blended.

Pour batter into prepared pan and spread evenly. Bake in preheated 350 degree oven 20 minutes or until pick inserted in center comes out clean. Cool in pan on rack 5 minutes. Loosen edges of cake with thin-bladed spatula. Sprinkle clean dish towel generously with granulated sugar and invert cake onto towel. Peel off paper. Starting at short end, roll up cake and towel as for jelly roll. Cool on rack. Unroll. Spread cake with cream filling. Reroll without towel. Place on platter. Frost with thin chocolate glaze. Chill several hours or overnight.

Cream Filling: In small mixing bowl, whip heavy cream and confectioners' sugar until soft peaks form. Do Not Overwhip.

Thin Chocolate Glaze: In small saucepan melt chocolate. Stir in hot water until smooth. Spread thinly over roll. Makes 10-12 servings.