Preheat oven to 350 degrees and spray muffin cups with cooking spray.
Add 1 teaspoon of melted butter into the bottom of each sprayed muffin cup.
Press 1 tablespoon of brown sugar in each muffin cup.
Press a maraschino cherry in to the center of the brown sugar in each muffin cup.
Add a large tablespoon of crushed pineapple over the cherry and press with the back of a spoon evenly.
Mix cake mix according to the package directions, replacing the water with pineapple juice. The amount of juice you'll need will vary based on which cake mix you use.
Pour pineapple cake batter into the muffin cups, leaving room at the top so they don't overflow.
Bake on the middle rack for about 20 minutes. Check consistency starting at 15 minutes so they don't burn.
Allow the mini cakes to cool before removing them from the cups.
Serve with pineapple and cherry sides up and enjoy!