Step 1

Combine rum and juice in a glass measuring cup. Heat 2 tablespoons butter in large skillet over medium-high heat until foaming. Add half of the pineapple slices, and cook until well browned on both sides, 5 to 8 minutes. Transfer to baking pan.

Step 2

Sprinkle pan with 1/4 cup sugar, and cook until sugar caramelizes to a golden brown, 1 to 2 minutes.

Step 3

Turn heat off or hold skillet away from heat, and carefully add 1/2 cup rum mixture.

Step 4

Turn heat on or return pan to heat and stir with a wooden spoon, scraping loose any caramelized bits on bottom of skillet. Simmer sauce until reduced and slightly thickened, about 3 minutes. Pour through fine sieve into a bowl, and set aside. Wash skillet, and repeat. Cut pineapple slices, and serve over ice cream drizzled with warm sauce.