Directions
Line an 8 x 8 x 2 in [20 x 20 x 5 cm] baking pan with parchment paper along the bottom, up the sides, and overhanging the sides by about 1 in [2.5 cm].
Melt the chocolate condensed milk, and butter together using a hot water bath or the microwave oven. Stir until completely melted and smooth. Remove the bowl from the water if you used a hot water bath and mix in the nuts (if using). Pour batter into the prepared pan, spread evenly, and let cool for 2 hours, or until firm.
Use the parchment paper to carefully lift the fudge out of the pan. Place the fudge on a cutting board, discard the parchment, and cut it into 1 ½ in [4 cm] squares. Store in an airtight container in the refrigerator for up to 10 days.
Variation for layered fudge: Pour half the batter into the prepared pan and spread it evenly. Spread a second layer of ½ cup [125 g] peanut butter, ½ cup [115 g] salted caramel, or ½ cup [35 g] marshmallow cream. Then pour in the rest of the batter and spread evenly. Let the fudge cool for 2 hours. When you're ready to serve, cut into 1 ½ in [4 cm] squares. Store, wrapped tightly, in the refrigerator for up to 10 days.
This recipe is courtesy of Amy Guittard from her Guittard Chocolate Cookbook.