Preheat broiler. Lay drained pineapple rings in a single layer on a 9- by 13-inch pan with sides -- allow edges of pineapple rings to touch.

Place a cherry in the center of each pineapple ring. Sprinkle each pineapple ring with 1 teaspoon brown sugar, then drizzle with 1/2 teaspoon margarine. Sprinkle with cinnamon.

Place 5 inches from broiler and broil (with oven door cracked) for 5 minutes or until topping is bubbly.