Beat together the eggs, milk and sugar. Add the cheeses and butter. Mix well then add the flour and baking powder. Pour into a greased 9x13 glass baking dish. Bake in a 325 degree oven for 45 minutes or until a knife inserted in the center comes out clean. This may be made ahead of time and refrigerated. If the pan goes from the refrigerator to the oven, bake 60 minutes.