Preparation - Combine the flour, baking powder and salt. In a separate bowl, beat the egg yolks, water, and sugar together. Add the flour mixture and beat for 2 to 3 minutes at medium speed. Fold in the beaten egg whites. Pour the batter into an 8" or 9" cake pan that has been very lightly sprayed with non-stick cooking spray. Bake in a preheated oven at 350º for 40 to 45 minutes or until the cake is golden brown and the center of the cake springs back when pressed lightly. Run a knife around the edge of the cake to free it from the sides of the pan. Turn the cake out of the pan onto a wire rack to cool.