In bottom of double boiler, heat cream till scalded. In double-boiler top, beat yolks with granulated sugar. Slowly stir cream into yolks.
Cook mixture over hot, not boiling, water until it coats spoon. Add vanilla. Refrigerate in 1- to 1 1/2-qt. ovenware casserole or flat baking dish.
Just before serving:
Over custard, sprinkle brown sugar.
Set custard dish in pan; surround with ice cubes. Broil custard till sugar caramelizes--about 1 min.
Breaking brown-sugar crust by tapping with spoon, serve at once over fruits, in nappy dishes or sherbet glasses. Makes 6 servings.