Prepare your favourite brownie recipe. Cut into 6 triangles and set aside. Mix green food colouring into pre-made buttercream icing until your icing is your desired shade of green. Spoon icing into piping bag and ice a zig-zag onto each brownie triangle. Decorate each brownie with red MnMs and sprinkles for Christmas baubles. Snap the curved ends of candy canes off and insert the remaining candy cane sticks into the base of your brownies.