Spray the bottom of a 6-quart Crockpot with non-stick cooking spray. Coat it well.
Melt the butter and then mix brown sugar into the melted butter.
Spread the butter and brown sugar mixture on the bottom of the Crockpot.
Drain the pineapple slices and then arrange on top of the brown sugar. Place them as close together as possible without overlapping.
Place a Maraschino cherry in the middle of each pineapple slice and in the spaces between the slices.
Prepare the cake mix according to the directions on the packaging. Use 1 cup of Sparkling Ice Coconut Pineapple instead of water.
Pour the cake batter over the pineapple and cherries layer.
Place the cover on your Crockpot and cook on HIGH for 2-3 hours. We generally let ours go for 3 hours to make sure it is fully cooked.
Turn off the slow cooker and remove the lid. Place the slow cooker crock on a cooling rack and allow the cake to cook for at least 15 minutes before you flip it onto your serving dish.
Notes
If you don't have Sparkling Ice, you can reserve the pineapple juice when you drain the slices. Then add water to the juice until you have a total of 1 cup of liquid. Use that liquid in place of the water used in the cake mix directions.