Take your square cake when cool, and measure 4.5 inches down from the corner and cut diagonally across to the opposite corner. The large piece is the witches' face, the other her hat.
From the shortest side of the face piece, cut off a wedge 2 by 3.5 inches to use for a nose. Tint frosting desired colors and assemble the cake on a large board or tray.
Frost cake and add coconut for hair. Place candies for eye and mouth.