Heat oven to 375 degree.
Line jelly roll pan, 15 1/2 x 10 1/2 x 1 inch, with aluminum foil or waxed paper: grease.
Stir together flour, cocoa, baking powder and salt; set aside.
In small mixer bowl, beat eggs about 5 minutes or until very thick and lemon colored.
Pour eggs into large mixer bowl; gradually beat in granulated sugar.
On low speed, blend in water and vanilla.
Gradually add flour mixture, beating just until batter is smooth.
Pour into pan, spreading batter to corners.
Bake 12 to 15 minutes or until wooden pick inserted in center comes out clean.
Loosen cake from edges of pan; invert on towel sprinkled with confectioners' sugar.
Carefully remove foil, trim off stiff edges if necessary.
While hot, roll cake and towel from narrow end.
Cool on wire rack.
Unroll cake; remove towel spread Whipped cream over cake.
Roll up; sprinkle with confectioners sugar or, if desired, frost with Chocolate Glaze.
