Heat 1/2 cup whipping cream and chocolate morsels in a saucepan over low heat, stirring until chocolate melts. Cool slightly. Pour mixture evenly into 6 (6-ounce) round individual baking dishes. Set aside.
Whisk together remaining 2 cups whipping cream, egg yolks, 1/2 cup sugar, and vanilla until sugar dissolves and mixture is smooth. Pour evenly into prepared baking dishes; place dishes in a 13- x 9-inch baking dish. Add hot water to large dish to a depth of 1/2 inch.
Bake at 275° for 1 hour and 10 minutes or until almost set. Cool custards in water in pan on a wire rack. Remove custards from pan; cover and chill at least 8 hours.
Sprinkle 1 tablespoon brown sugar over each custard; place custards in baking pan.
Broil 5 1/2 inches from heat until sugar melts. Let stand 5 minutes to allow sugar to harden.