Cream butter and 300g sugar then add eggs, flour and sugar. Bake in a base (preferably a cast iron pan), at 180C for 20-30 mins. Test with a skewer. Peel apple or pear and core. Slice, then cover the base. Sprinkle sugar over and bake till the apple\pear is soft and a golden brown colour. To serve, place a plate over the baking pan and tip upside down.