Into a medium mixing bowl, sift together the sifted flour, granulated sugar, baking powder, and salt. Add remaining ingredients and blend on low speed of electric mixer. Increase mixer speed to medium and beat for 2 minutes. Spread batter over peaches. Bake at 375° for 40 minutes, or until a wooden pick or cake tester inserted in center comes out with no cake batter clinging. Cool in pan for a minute or two before turning out onto serving plate. Serve warm, with whipped topping or ice cream if desired.