I'm a big fan of cooked pineapple. This cake can be topped with whipped cream or ice cream and make a pretty dessert for your table.
Spray a 6-quart slow cooker with a cooking spray. Mix the brown sugar and butter together and spread in the bottom of the pot. Arrange the pineapple slices on top of the sugar mixture. Place a cherry in the middle of each pineapple ring.
Add water to the reserved pineapple juice so that it measures one cup. Make cake batter as directed on the box, but substitute the water for pineapple juice. Pour batter into the crockpot.
Cook on high for 2-1/2 to 3 hours. A toothpick in the center should come out clean. Remove pot from the slow cooker and place on a cooling rack for 15 minutes.
Place a plate upside down on the pot. Carefully turn over to remove the cake.