Preheat oven to 350° and grease a bundt pan (generously) with cooking spray. In a medium bowl, whisk together melted butter and brown sugar, then pour mixture into bottom of bundt pan.

Place halved pineapple rings and cherries around the bottom of the pan, alternating between each. Add pineapple chunks between the rings and cherries.

In a large bowl, beat together cake mix, vegetable oil, pineapple juice, and eggs. Pour batter over pineapples and cherries. Bake until a toothpick comes out clean, about 35 minutes.

Let cake cool for 10 minutes in pan, then slide a knife (or a small offset spatula) around edges and center to release cake from pan. Invert cake onto serving tray.

Serve warm or at room temperature, slicing cake between pineapples.