Preheat the oven to 400 degrees. Grease a 9-inch round, 1 1/2-inch deep cake pan. With a fork, stir together the cake flour, cornmeal, baking powder, salt and sugar. Beat the egg, melted butter, oil and milk in a large mixing bowl until well blended. Add the dry ingredients to the egg mixture and stir until blended. The batter will be somewhat thin and light.