This is a very sweet dessert to end a hearty meal.
Melt butter in a medium saute pan over low heat. Add sugar and stir until melted. Add pineapple, rum, if desired, and vanilla, and turn heat up to medium high.
Cook, stirring, until liquid is reduced and pineapple is glazed, about 15 minutes. Be careful not to burn.
Serve in bowls with a scoop of ice cream.
Choose a sweet-smelling pineapple that yields to gentle pressure but doesn't have soft spots.