Preheat oven to 450 degrees. In a large skillet, saute sausage until browned. Pour off and fat from skillet, add apple slices, sprinkle with sugar and cinnamon. Saute 1 to 2 minutes until apples just lose their crispness. Set aside. Place the butter in a well-seasoned 9-inch iron skillet and heat in preheated oven until bubbly and hot. Arrange the sausage in the pan, cover with apples, distributing evenly. Pour the batter over the apples and bake until nicely browned, about 8 to 10 minutes. Cut into pie shaped wedges and serve immediately.