broiled grapefruit ambrosia

Heat the broiler. With a sharp knife; cut the peel and membrane from the grapefruits and oranges. Cut the fruit crosswise into ½-inch-thick slices. In a shallow gratin baking dish or cast-iron skillet; alternately arrange the grapefruit and orange slices. Sprinkle with brown sugar and dot with butter. Broil the fruit until it is hot and lightly browned; about 5 minutes. Sprinkle with coconut and broil just until the coconut is toasted. Serve immediately.