Prepare brownies as directed on package, stirring chocolate chips or walnut pieces into batter before baking. Let brownies cool, cut into 4 cm squares and refrigerate for 2 hours.
To prepare icing, cream together butter, salt, peppermint extract and confectioners sugar until smooth. Spread over brownies. Let icing set. Spread chocolate fudge topping over the top of each frosted brownie square. Place the brownies in the freezer for 5-10 minutes. Remove and serve or keep in a cool spot until serving.
Yield: 24