Use a metal pan that will fit into the dutch oven *or* use foil. Put the pan into the oven so that it rests above or on top of 1/2 inch of water in the bottom of the oven. If you are using foil, wrap the foil over the sides of the dutch oven, so that you have a "pan" inside that just rests on top of the water/other but won't fall in. Use several layers of foil. Put dots of butter in pan. Sprinkle brown sugar over bottom. Place pineapple slices in a single layer on the bottom. Place maraschino cherries in the holes in the pineapple slices. Pour cake batter over this. Close up dutch oven, place coals on top if desired or possible, and bake until done. Also, you can include walnuts.