How to Make It
Preheat the broiler.
Cut the mangoes lengthwise around the pits, discarding the pits. Using the tip of a knife, score the flesh of the mangoes with 1/2-inch hatch-mark cuts. Sprinkle the mangoes with the sugar and drizzle with the rum. Broil the mangoes 3 to 4 inches from the heat until browned in spots. Serve warm, topped with vanilla ice cream.