Preheat the oven to 350°F and lightly grease a 9x13-inch baking dish.

Melt the butter in the microwave, then pour it into the greased baking dish. Tilt the pan to spread the butter across the bottom. Sprinkle the brown sugar evenly over the melted butter.

Place pineapple rings over the brown sugar layer. Add maraschino cherries in the centers of the pineapple rings and in any gaps.

(Technically you can use just one can of pineapple, but if you want the cake fully covered and more decorative, use two cans to really deck it out.)

In a large bowl, add the cake mix, oil, eggs, and 1 cup pineapple juice (top up with water if needed). Whisk just until combined. A few small lumps are fine.

Pour the prepared batter gently over the pineapple and cherries, spreading it evenly. Bake for about 40 minutes, or until a toothpick inserted in the center comes out clean.

Allow the cake to sit in the pan for 5 minutes after baking.

Place a large rimmed baking sheet or tray upside down over the baking dish.

Hold the tray and baking dish firmly together and quickly but carefully flip them over. Lift the baking dish slowly to reveal the cake.

Let the cake cool completely before slicing. Serve and enjoy!