Line the Baking Pan:
Begin by lining an 8×8-inch baking pan with parchment paper. Make sure to leave overhang on two sides to make it easier to lift the fudge out later. Set the pan aside for now.
Boil the Base:
In a medium saucepan, combine the granulated sugar, evaporated milk, unsalted butter, and fine sea salt. Place the pan over medium heat and stir constantly with a heatproof spatula. Bring the mixture to a full rolling boil. This means you should see large bubbles form rapidly, and the mixture should be boiling throughout. Once boiling, set a timer and continue to cook for exactly 5 minutes while stirring. This step is crucial because it ensures proper sugar dissolution and sets the fudge texture.
Melt the Chocolate:
After the 5-minute boiling time, remove the saucepan from the heat. Immediately add the milk chocolate chips to the hot mixture. Let the chips sit for about 1 minute to soften, then stir gently until the chocolate is fully melted and the mixture is glossy. The chocolate should blend seamlessly into the mixture, creating a smooth and rich fudge base.
Fold in Softeners:
Add the fresh marshmallows, vanilla extract, and chopped walnuts or pecans (if using). Stir vigorously but smoothly for 1–2 minutes until the marshmallows are just melted, and the fudge mixture is thick, shiny, and uniform. Be sure to stir evenly so that all the ingredients are well incorporated. Note: Fresh marshmallows melt more easily, while stale marshmallows can make the fudge chewy or lumpy.
Pour & Set:
Scrape the fudge mixture into the prepared baking pan. Use a spatula to smooth the top, and for an even finish, you can wet the spatula slightly to help prevent sticking. Let the fudge cool at room temperature for about 30 minutes, then refrigerate uncovered for 1–2 hours, or until the fudge is firm to the touch.
Lift & Cut:
Once the fudge has set, lift it out of the pan using the parchment paper overhang. Place it on a cutting board and cut it into 1-inch squares with a sharp knife. To ensure clean edges, wipe the knife between cuts.
Storage:
Store the fudge in an airtight container at room temperature for up to 1 week or in the fridge for up to 2 weeks. Be sure to keep it sealed to maintain its freshness and texture.
