Melt the butter and divide between two 8" cake pans.
Sprinkle the brown sugar evenly to cover the butter (divided as well).
Next, arrange pineapple rings around the bottom of the pans, one layer deep (I had 5 rings per pan). Place a maraschino cherry into the center of each pinapple ring (and a few in the middle if you would like).
Prepare the cake mix as directed above. Pour the batter over the pineapple layer (dividing the batter between the two pans).
Bake for 25-30 minutes at 350 degrees F (or as directed cake mix directions). Cool for 5 minutes, then carefully turn out onto a plate. Do not let the cake coo too much, or it will be stuck to the pan.