1 package fudge brownie mix (13-in. x 9-in. pan size)
6 tablespoons butter, softened
2-3/4 cups confectioners' sugar
1/2 cup baking cocoa
1/3 cup milk
1 teaspoon vanilla extract
1/4 cup vanilla or white chips
Prepare the brownie batter according to package directions. Spread into a greased 15x10x1-in. baking pan. Bake at 350° for 13-15 minutes or until a toothpick comes out clean. Cool on a wire rack.
In a large bowl, beat the butter, sugar, cocoa, milk and vanilla until smooth. Frost the cooled brownies. Loosely cover and chill for 1 hour or until frosting is set.
With a sharp knife, make lengthwise cuts 1-1/2-in. parallel cuts from a short side to a long side to form diamonds. In a microwave, melt chocolate chips at 50% power; stir until smooth. Place in a small heavy-duty resealable plastic bag; cut a small hole in a corner of bag. Pipe laces on brownies.