Pour in some milk in the hole and start stirring. The butter should be very hot. Turn the pancake when the upper surface is dry and bake the reverse side for approx. You can use anythind you like as a filling, use your imagination. Savoury pizzatype fillings are nice and can be put on top of the pancake after it's baked.
Classic fillings are bacon and syrup pancakes and apple pancakes.
For the baconpancakes you have to fry the bacon first and then pour over the batter. They are served with dutch syrup, which has a thicker consistancy than american syrup. Here in Australia they sell cane molasses, and that tastes almost the same as dutch pancake syrup. These pancakes are great with applesyrup, but I'm not sure that't available in the States. Normal syrup or sugar and cinnamon will do as well I reckon.