Preheat oven to 350ºF.

Prepare mega muffin pan with vegetable pan spray.

Drain pineapple slices, reserving ½ cup juice.

In medium bowl, stir together butter and brown sugar. Divide evenly among cavities. Cut each pineapple slice into eight pieces. Divide pineapple among cavities, 3-4 in each.

In large bowl, beat cake mix, eggs, vegetable oil, coconut rum, and pineapple juice with electric mixer on low speed 30 seconds. Scrape bowl. Beat on medium speed 2 minutes. Divide batter evenly among cavities, pouring over pineapple slices. Nonalcholic Substitution: Substitute pineapple juice for coconut rum.

Bake 18-20 minutes or until toothpick inserted in center of cupcake comes out clean. Rotate pan halfway through baking. Cool cupcakes in pan on cooling grid 5 minutes. Remove from pan; cool completely on grid.

Top each with whipped cream and a maraschino cherry if desired.