Using a 360 Sauté pan or similar heavy pan, melt the butter over medium-high heat. Once the butter is melted, add the brown sugar, and let it dissolve completely. Next, add the pineapple rings or crushed pineapple and simmer until lightly caramelized.
While the pineapple is caramelizing, mix the cake mix with the eggs and liquid (Reserved juice and water).
Once the pineapple mixture is ready, poured the cake mix into the Sauté pan on low heat for 45 to 60 minutes. Let it cool and then take a plate put it on the top of the Pan and invert it.
Add Whip cream and maraschino cherries to the top of the Pineapple Upside Down Cake to complete it.