Cream sugar and butter well. Add beaten eggs, flour, cocoa and salt and mix until thoroughly combined. Bake in a greased 13x9 pan at 400F for 25 minutes.
While brownies are baking cream together the confectioners sugar, peppermint extract, softened butter and as much food coloring as desired in a bowl and set aside. Spread on brownies after they have cooled in the pan for 15 minutes.
When brownies are completely cool, melt together the chocolate chips and 6Tbsp butter. Spread immediately on top of mint layer of brownies. Chill until set, but soft enough to cut. If chocolate is too hard it will crack and make it difficult to cut brownies squares.