Granddad's Peppermint Fudge

My mum was the owner of this recipe. It’s one of her many Christmas cookies, which she has a lot of.

Ingredients

Put chocolate chips and marshmallow creme in a large mixing bowl with margarine.
Combine sugar and evaporated milk in a large pot over medium-low heat. Stir constantly and bring to a rolling boil. Reduce heat to low. Continue to stir gently, making sure you do not scrape the edge of the pot. Use a candy thermometer to keep an eye on the temperature, and heat mixture to 240 degrees F (115 degrees C), 7 to 10 minutes. A small amount of syrup dropped into cold water should form a soft ball that flattens when removed from the water and placed on a flat surface.
Pour hot sugar mixture over the ingredients in the mixing bowl; stir until combined. Stir in vanilla and peppermint extract until well combined.
Line a 9×13-inch rimmed baking sheet with waxed paper. Pour in fudge mixture and cool in the refrigerator until completely set, about 2 hours.
Remove fudge from the refrigerator. Run a sharp knife under hot water and cut fudge into 1-inch squares.
Dark chocolate chips work in place of semisweet.
For balled or piped fudge: Beat fudge in an electric mixer until it cools enough to hold its shape when dropped, about 15 minutes. Use 2 spoons to scoop and ball fudge onto waxed paper. Or put fudge in a silicone piping bag fitted with a large tip and pipe rosettes on waxed paper. Stir fudge regularly to keep it from hardening while you work.