Apple Cinnamon Bundt Cake

1 egg
1/2 cup sugar
2 tablespoons oil
1 1/4 cups buttermilk
1 teaspoon vanilla
1 cup whole wheat flour
1 cup all-purpose flour
2 teaspoons baking powder
1 apple; peel, core, thinly sliced
2 tablespoons cinnamon sugar


Beat together first 5 ingredients until blended. Beat in the next 3 ingredients until blended. Place batter in lightly oiled 10-inch spring form pan and place apples decoratively on top. Sprinkle top with cinnamon sugar. Bake at 350 degrees for about 35-40 minutes, or until a cake tester inserted in center, comes out clean. Allow to cool in pan. When cool, remove from pan and sprinkle with 1 teaspoon sifted powdered sugar.