Prepare Your Pan: Grease a 9x13-inch pan with margarine to ensure the fudge doesn’t stick. This step is crucial for easy removal later on.
Combine Ingredients: In a medium-sized saucepan, combine 3 cups of sugar, 3/4 cup of margarine, and 2/3 cup of evaporated milk. Heat over medium heat and stir until the sugar dissolves, which typically takes about 2-3 minutes.
Bring to a Boil: Once the sugar is dissolved, increase the heat and bring the mixture to a boil. Stir continuously for 5 minutes. You'll know it's ready when the mixture starts to thicken slightly.
Incorporate Chocolate: Remove the saucepan from heat. Add 12 oz. of chocolate chips to the hot mixture. Stir until the chocolate chips fully melt and the mixture is smooth. This step is where the magic happens, turning your mixture into a rich, chocolatey delight.
Add the Rest: Mix in 7 oz. of marshmallow cream, 1 cup of chopped walnuts, and 1 tsp of vanilla extract. Stir until everything is evenly combined.
Pour and Cool: Pour the fudge mixture into the greased pan, spreading it evenly if needed. Allow it to cool for about 1 hour at room temperature. Once cooled, cut the fudge into squares and serve. Enjoy your delightful creation!