Move the oven rack to the middle position. Preheat the oven to 350 degrees F.
Grease a 9x13 baking pan with nonstick cooking spray.
Spread the crushed pineapple and juices into the bottom of the prepared baking pan.
Spread the cherry pie filling on top of the crushed pineapple layer.
Sprinkle the dry cake mix evenly across the top of the cherry pie filling.
Place the 24 pieces of butter on top of the dry cake mix.
Bake for 45-55 minutes, check the cake halfway through baking, if there are flour pockets, then use a fork to mix them into the cake. You’ll know when the cake is done, because it will be bubbly and the top cake layer will be slightly golden brown.
Allow the cake to cool slightly. Then serve with vanilla ice cream or whipped cream (both optional).
Store in an airtight container for up to 5 days in the refrigerator.