PREHEAT oven to 350° F. Grease 9-inch-square baking pan.
COMBINE flour, baking soda and salt in small bowl. Combine sugar, butter and water in medium saucepan. Bring just to a boil over medium heat, stirring constantly; remove from heat. (Or, combine sugar, butter and water in medium, microwave-safe bowl. Microwave on HIGH (100%) power for 3 minutes, stirring halfway through cooking time. Stir until smooth.)
ADD 1 cup morsels, peppermint extract and vanilla extract; stir until smooth. Add eggs, one at a time, stirring well after each addition. Stir in flour mixture and remaining morsels. Spread into prepared baking pan.
BAKE for 20 to 30 minutes or until center is set. Cool completely (center will sink) in pan on wire rack.
SPREAD vanilla frosting over brownie. Squeeze chocolate icing in parallel lines over frosting. Drag wooden pick through chocolate icing to feather. Let stand until frosting is set. Cut into bars.