Start by lining an 8x8 inch baking pan with parchment paper or aluminum foil, allowing some overhang for easy removal later.

In a medium saucepan, combine semi-sweet chocolate chips, sweetened condensed milk, unsalted butter, and a pinch of salt. Set the heat to low and continuously stir the mixture for about 5–7 minutes.

Once your chocolate mixture is smooth and glossy, remove from heat. Stir in the peppermint extract and chopped Andes Mints until evenly distributed.

Carefully pour the warm fudge mixture into the prepared pan and spread it evenly using a spatula.

If desired, sprinkle additional chopped Andes Mints or crushed candy canes on top of the fudge and press gently into the surface.

Place the pan in the refrigerator and chill for at least 2 hours, or until firm.

Once chilled, lift the fudge out using the overhanging edges of the parchment paper and slice into squares for serving.