Drain the pineapples and reserve the juice.
Melt the butter in a small pot over medium heat. Add the brown sugar, and mix together.
Spray the the insides of a muffin pan, and evenly divide the butter/ sugar mixture and pour into the muffin cups.
Press the pineapple slices on top of the sugar mixture.
Place the cherries in the center of the pineapple, sliced side up.
Prepare the cake mix according the package instructions, substituting the water for the reserved pineapple juice.
Pour the cake batter on top of the pineapple slices. Fill 2/3 of the muffin cup.
Bake at 350 degrees for 20-25 minutes, or until baked through.
Cool 5 minutes. Loosen edges and invert cakes onto a cooling rack.