Build the pineapple layer: Pour the melted butter into the bottom of the pan and spread evenly. Sprinkle the brown sugar over the butter, then arrange the pineapple rings on top in a single layer, placing a cherry in the center of each ring.

Make the cheesecake layer: Beat the softened cream cheese and sugar together until smooth and no lumps remain. Add the egg, vanilla, and sour cream, mixing just until combined overbeating at this stage can incorporate too much air and cause cracking later. Pour this mixture carefully over the pineapple layer, spreading it into an even layer.

Mix and add the cake batter: Prepare the cake mix according to the box instructions, substituting the reserved pineapple juice for part of the water. Gently spoon the batter over the cheesecake layer, spreading carefully so the layers don’t mix together.

Bake until set: Bake for 50–55 minutes, until the top is golden and a toothpick inserted into the cake layer comes out clean. The cheesecake layer underneath will still look slightly soft through the cake that’s expected at this stage.

Cool completely, then chill overnight this is the step that actually determines success: Let the cake cool at room temperature for about an hour, then refrigerate for a minimum of 4 hours, ideally overnight. The cheesecake layer needs this full chilling time to firm up completely; flipping it while still warm or only partially set is exactly what causes the layers to collapse or slide apart the extra patience here is what keeps the pineapple and cheesecake layers distinct instead of merging into a soggy mess.

Flip and serve: Run a thin knife around the edges of the pan to loosen it, place a serving platter over the top, and carefully invert the pan. Lift the pan away slowly, then peel off the parchment paper. Slice and serve chilled or slightly cooled.