Line a 9x13-inch baking dish with parchment paper (or foil) and coat the paper with nonstick cooking spray. Place a large Swiss Diamond non-stick saucepan over medium-low heat. Pour one can of sweetened condensed milk into the pot and add the chocolate chips. Stir until the chocolate has melted into the sweetened condensed milk. Then pour the mixture into the prepared baking sheet. (If you use darker chocolate, the mixture will turn into a thicker paste that must be spread into the dish, not poured.)
Rinse the pot out with water and dry with a paper towel, then set back over the heat. Pour another can of sweetened condensed milk into the pot. Add 3 cups of chopped white almond bark, 1 teaspoon peppermint extract, and 1-3 drops of red food coloring. Stir until the almond bark melts. Then pour the peppermint layer over the chocolate.
Rinse the pot out with water again and dry with a paper towel, then set back over the heat one last time. Pour the last can of sweetened condensed milk into the pot. Add 3 cups of chopped white almond bark and stir until the almond bark melts. Then pour the white chocolate layer over the peppermint layer.
Place the pan in the refrigerator and chill until firm, 1-2 hours. Then lift the fudge out of the pan by the edges of the paper. Cut into squares. Keep in an airtight container until ready to serve.