Grease a 9x13" pan.
Mix sugar, margarine and evaporated milk in a large, heavy saucepan over medium heat, stirring to dissolve sugar.
Boil 4 minutes or until candy thermometer reaches 234 degrees F, stirring constantly to prevent scorching. Remove from heat.
Stir in chocolate chips until melted and thoroughly combined.
Beat in marshmallow creme, walnuts and vanilla.
Transfer fudge to the prepared pan and let cool before cutting into squares.
Dad’s tips: Always have everything measured and ready to go. When the mixture reaches the correct temperature it’s best to be ready to act fast. Soak the jar of marshmallow creme in warm or hot water for a few minutes to make it easier to get it out of jar.