Melt butter in a large skillet. Add brown sugar and stir together. Add the bananas and cook until caramelized over medium-high heat. Pour in the rum and catch a flame off of the gas stove or a BBQ lighter. Stand back when ignited and flambe. Be careful; a flame will shoot up above the pan. Let flame die down. Serve over vanilla ice cream and/or a slice of pound cake.
Use extreme caution when igniting alcohol. Remove the pan from the heat source before adding the alcohol. Pour the alcohol into the pan and carefully ignite with a match or click lighter. Return the pan to the heat and gently swirl to reduce the flames.