Heat oven to 375 degrees.
Grease sides of 15 x 10 x 1-inch jelly roll pan and line bottom with waxed paper or greased heavy brown paper.
Beat eggs in small mixer bowl until very thick and fluffy.
Add sugar gradually and beat well after each addition.
Beat in water and vanilla.
Sift flour, baking powder and salt together into egg mixture and beat until smooth.
Pour into prepared pan and spread evenly.
Bake 12 to 15 minutes or until top springs back when touched lightly in centre.
Sift icing sugar over top of cake and turn out on towel.
Roll cake and towel up together loosely from narrow end and let stand on cake rack until cool .
Unroll and spread cake with jam or jelly and roll up again.
Sprinkle top with more icing sugar if desired.
Cut in thick slices to serve.