01 - In a large mixing bowl, combine powdered sugar, unsalted butter, peppermint extract, heavy cream, and salt. Mix with an electric mixer or sturdy spatula until a smooth, pliable dough is achieved. If the dough remains sticky, incrementally mix in additional powdered sugar until it can be easily handled.
02 - Scoop portions of dough, about 2 teaspoons each, and gently roll into balls. Flatten each into 1/4-inch thick discs and position on a parchment-lined baking sheet.
03 - Place the baking sheet in the freezer for 20 to 30 minutes or until the discs are firm to the touch.
04 - Set a heatproof bowl over a pot of gently simmering water. Add chopped dark chocolate and coconut oil if using, stirring constantly until chocolate is fully melted and glossy.
05 - Using a fork, dip each chilled peppermint disc fully into the melted chocolate. Allow excess chocolate to drip away before returning each disc to the parchment-lined baking sheet.
06 - Refrigerate coated patties for 15 minutes, or until the chocolate shell is completely firm.