Prepare the Chocolate Layer

1. Melt Chocolate: In a medium saucepan over low heat, combine the semi-sweet chocolate chips and sweetened condensed milk. Stir constantly until smooth and melted.
2. Mix in Cocoa: Add unsweetened cocoa powder, peppermint extract, and salt. Stir until well combined and smooth.
3. Spread Layer: Pour the chocolate mixture into a greased 8×8-inch baking dish and spread evenly.

Chill the Chocolate Layer

1. Cool: Allow the chocolate layer to cool at room temperature for about 15 minutes, then place it in the refrigerator to set for approximately 1 hour.

Prepare the Mint Layer

1. Melt White Chocolate: In another saucepan, melt the white chocolate chips and sweetened condensed milk over low heat, stirring until smooth.
2. Add Mint Flavor: Stir in the peppermint extract and a few drops of green food coloring if desired, mixing until fully incorporated.
3. Spread Mint Layer: Pour the mint layer over the cooled chocolate layer, spreading it evenly.

Chill the Fudge

1. Set Fudge: Return the dish to the refrigerator for another 40 minutes, or until fully set.
2. Cut into Pieces: Once set, remove from the fridge and cut into squares.

Serve and Enjoy

1. Garnish (optional): Top with crushed peppermint candies or chocolate shavings for an extra festive touch.
2. Store: Keep any leftover fudge in an airtight container at room temperature or in the fridge.