Line one 9x9 square pan with aluminum foil. Add sugar, butter, heavy cream, and salt to a medium-sized, deep pot and bring to a boil. Boil for five minutes, stirring occasionally.
Remove from heat and, using an electric mixer, beat in fluff. Stir in white chocolate and mint extract and beat until smooth.
Divide amongst 3 bowls. Dye one batch of fudge red, one batch green, and leave the last white. Pour the white layer into the prepared pan, followed by the next two colors. Top with crushed candy canes, and then cover and place in fridge to set for at least 4 hours. Cut into squares and serve.
