Line an 8x8-inch pan with aluminum foil, leaving some overhang on the sides. This will make it easier to remove the fudge later.
In a medium saucepan, combine the chocolate chips, sweetened condensed milk, and butter. Heat over medium-low, stirring constantly for about 5-7 minutes, until the mixture is smooth and fully melted. While it may be tempting, do not turn up the heat - chocolate burns easily. This is a low and slow process with stirring. The fudge will start to thicken like frosting. Remove from heat.
12 oz semi-sweet chocolate chips, 14 oz sweetened condensed milk, 2 tablespoons butter
Stir in the peppermint oil or extract until fully mixed, which should take about a minute.
1/4 teaspoon peppermint oil
Pour the fudge mixture into your prepared pan, using a spatula to spread it evenly.
Sprinkle the chopped Andes mints on top. Press them gently into the fudge so they stay in place.
16 Andes Creme De Menthe Thin Mints
Refrigerate the pan for at least 2-3 hours, or until the fudge is firm and set. You can also leave it overnight if needed.
Once set, lift the fudge out of the pan using the foil overhang. Peel off the foil and cut the fudge into small squares. Enjoy!
Notes
What if I don’t have peppermint oil? You can easily substitute peppermint extract for the oil in this recipe. Just remember that extracts are usually weaker than oils, so you may need to adjust the quantity to taste. Start with 1/2 teaspoon of peppermint extract if you make the switch.