Prepare the Filling

1. Mix the Filling: In a large mixing bowl, combine powdered sugar, cocoa powder, sweetened condensed milk, peppermint extract, and salt. Mix until a dough forms.
2. Roll the Mixture: Dust your hands with powdered sugar and roll the mixture into small balls, then flatten them into discs about 1/4 inch thick.
3. Chill: Place the discs on a parchment-lined baking sheet and chill in the refrigerator for about 1 hour until firm.

Coat the Patties

1. Melt the Chocolate: In a microwave-safe bowl, melt dark chocolate chips and coconut oil (if using) in 30-second intervals, stirring until smooth.
2. Dip the Patties: Using a fork or dipping tool, dip each chilled peppermint patty into the melted chocolate, ensuring it is fully coated. Tap off any excess chocolate.
3. Set on Baking Sheet: Place the chocolate-covered patties back on the parchment-lined baking sheet.

Let Them Set

1. Chill Again: Refrigerate the patties for an additional 30 minutes to allow the chocolate to set completely.