How to Make It
In a heavy medium saucepan, simmer the sugar and water over high heat, stirring gently, until the sugar dissolves. Lower the heat to moderate and simmer undisturbed until a deep amber caramel forms, about 12 minutes. Remove from the heat. Gradually stir in the cream. Stir in the butter and rum. Transfer the sauce to a bowl and let cool. Stir in the pineapple and serve.