Preheat the broiler. Remove skin and "eyes" from pineapples and slice into 3/4-inch rounds; remove core if you wish or just thickly coat each slice with a layer of brown sugar. Set slices on a broiler pan.
Place the pan under the broiler as close to the heat as possible and broil until the sugar is caramelized, about 3 minutes keep your eye on the pineapple to make sure it does not burn.
Remove slices from the broiler pan and set on plates; garnish with drops of port wine if you wish.