Step 1: Prepare Your Pan - Start by lining a 9x13 inch baking pan with parchment paper. Leave a little overhang on the sides to make it easier to lift the fudge out later. Set aside.
Step 2: Combine Ingredients - In a heavy-bottomed saucepan, combine the granulated sugar, salted butter, and evaporated milk. Stir the mixture over medium heat until the sugar dissolves.
Step 3: Bring to a Boil - Once the sugar is dissolved, increase the heat and bring the mixture to a rolling boil. Stir continuously for about 5 minutes. Make sure to monitor the temperature to prevent burning.
Step 4: Add Chocolate and Fluff - Remove the saucepan from heat and stir in the chocolate chips and marshmallow fluff. Mix until everything is completely melted and smooth.
Step 5: Stir in Nuts and Vanilla - Add the chopped walnuts and vanilla extract to the chocolate mixture. Stir until the nuts are evenly distributed throughout.
Step 6: Pour and Set - Quickly pour the fudge mixture into the prepared baking pan, spreading it evenly. Allow it to cool at room temperature for about 2 hours or until set.
Step 7: Cut and Serve - Once set, use the parchment paper overhang to lift the fudge out of the pan. Cut into squares and serve. Enjoy your delicious homemade Original Fantasy Fudge!