Grilled grapefruit

Cut a sliver off the top and bottom of 3 grapefruits so they stand upright. Then cut in half crossways. Using a grapefruit knife, cut around the segments in each half to loosen. Melt 1oz (25g) butter and, using a pastry brush, dab melted butter over the surface of each grapefruit half, then sprinkle generously with demerara sugar. Set grapefruit halves under a hot grill about 2 inches (5cm) from the heat. Grill for about 5 minutes until sugar has melted and is bubbling. Set in individual serving glasses.