In a large mixing bowl, sift together the powdered sugar and cornstarch until well combined.
Add the sweetened condensed milk, peppermint extract, and vanilla extract to the dry ingredients. Mix with a spatula until a dough forms.
If the dough is too sticky, gradually add more powdered sugar until it reaches a pliable consistency.
Divide the dough into small pieces and shape each piece into rounded discs, about 1-inch in diameter and 1/4-inch thick, ensuring they are flat.
Place the shaped patties on a parchment-lined baking sheet and freeze for about 30 minutes until firm.
In a microwave-safe bowl, combine the dark chocolate chips and coconut oil. Heat in the microwave in 30-second intervals, stirring in between, until the chocolate is completely melted and smooth.
Remove the patties from the freezer. Dip each patty into the melted chocolate, ensuring they are fully coated. Let excess chocolate drip off.
Place the chocolate-coated patties back on the parchment-lined baking sheet. Repeat until all patties are coated.
For an added touch, you can sprinkle crushed peppermint candies on top of the chocolate before it sets.
Allow the patties to sit at room temperature or place them in the fridge to let the chocolate harden.
Notes
For an added touch, sprinkle crushed peppermint candies on top before the chocolate sets.