Separate eggs. Allow egg whites to stand at room temperature for 30 minutes (reserve yolks for another use). Meanwhile, grease three 8x1-1/2-inch round cake pans. Line bottoms of pans with parchment paper. Grease parchment paper and lightly flour pans; set aside. In medium bowl stir together flour, baking powder, baking soda, and 3/4 teaspoon salt; set aside.