1tbspunsalted butter, plus more for greasing the dish
1tspvanilla extract
1/4tspsalt
1/4tsppeppermint extract
Instructions
Grease an 8x8 baking dish with butter. Optionally, you can add half the peppermint chunks to the bottom of the dish, instead of putting them all on top.
Pour the sweetened condensed milk and butter into the bowl of a double boiler over medium heat and heat up, ~1-2 minutes. Add the chocolate and salt to the bowl. Stir the chocolate until it melts. Keep stirring for a few minutes as the chocolate will start to thicken.
Add both the vanilla and peppermint extract and mix until fully combined. The mix should now be quite thick (almost too thick to pour). Take the bowl off the heat and pour the mix into the prepared dish. Sprinkle the top with the peppermint chunks, and chill in the fridge for at least 3 hours until set.
Once set, cut the fudge into 16 pieces. I found that a bench scraper works better than a knife for this. Run it under hot water for a minute or two to get it warm, and dry it with a paper towel before pressing it into the fudge to cut.