Line an 8x8 square pan with aluminum foil and lightly butter the sides and bottom of the foil.  Set aside.

Divide condensed milk equally into two separate small/medium saucepans (just over ½ cup in each pan).  1 14 oz can (396 g) sweetened condensed milk

Add dark chocolate chips to one pan and white chocolate chips to the other.1 cup (175 g) dark chocolate chips, 1 cup (175 g) premium white chocolate chips

Melt chocolate chips over medium heat, stirring constantly until completely melted.  Once chocolate has melted, remove dark chocolate mixture from heat and stir in vanilla extract.  Immediately spread evenly into prepared pan.½ teaspoon vanilla extract

Once white chocolate has melted, remove from heat and stir in mint extract, if using.  Stir in ¼ cup (50g) crushed peppermint pieces and immediately spread evenly over chocolate layer.¼ teaspoon peppermint extract, ⅓ cup (75 g) crushed candy canes

Immediately sprinkle with remaining crushed peppermint pieces.

Allow fudge to harden completely before slicing and serving (about 4-6 hours at room temperature, or about 1-2 hours in refrigerator).