Cut each grapefruit in half; remove centers.
Loosen all sections from skin with grapefruit knife; scallop or notch rims, but not very deep.
Place grapefruit in shallow baking dish; sprinkle each with 1 teaspoon Madeira and 1 tablespoon brown sugar.
Dot with butter.
Bake in preheated 350Â°F oven, 1 rack above center, 25 to 30 minutes or until grapefruits are heated through and tops are golden.
Place a cherry and a small fresh leaf, if available, in center of each grapefruit half.
Place grapefruit on serving platter.