Line your 9x13-inch baking dish with parchment paper, leaving some overhang on the sides.
In a medium saucepan, combine the granulated sugar, salted butter, and evaporated milk. Stir over medium heat until it comes to a full boil.
Once boiling, continue to stir for about 4-5 minutes until it reaches the soft ball stage (around 234°F).
Remove from heat and stir in the chocolate chips and marshmallow fluff until fully melted and smooth.
Add the chopped walnuts and vanilla extract, stirring until well combined.
Pour the fudge mixture into the prepared baking dish and spread it evenly. Allow it to cool at room temperature for about 2 hours until it’s set.
Once set, lift the fudge out using the parchment overhang, cut into squares, and enjoy!
