Stir together first 3 ingredients just until blended. Spoon mixture into a 10-oz. ramekin; level and smooth surface with a spatula. Cover and chill 2 to 8 hours.
Preheat broiler with oven rack 5 inches from heat. Sprinkle granulated sugar over mixture in ramekin. Fill an 8-inch cake pan with ice; place ramekin in pan.
Broil 3 to 5 minutes or until sugar is melted and caramelized. Let stand 5 minutes. Serve with apple slices.