1. Prepare the Mint Filling: In a mixing bowl, combine the sifted powdered sugar, softened butter, peppermint extract, and heavy cream. Beat until you have a smooth, slightly firm dough.
2. Shape the Patties: Scoop about a teaspoon of the filling, roll it into a small ball, and then gently flatten it into a small disc shape. Place these discs onto a baking sheet lined with parchment paper.
3. Chill Firmly: Pop the baking sheet into the freezer for about 20 minutes. This step makes dipping much easier!
4. Melt the Chocolate: While the patties chill, melt your chopped chocolate (and vegetable oil, if using) in a microwave-safe bowl. Heat in 30-second bursts, stirring well after each, until the chocolate is completely smooth and glossy.
5. Dip & Coat: Using a fork or a dipping tool, carefully dip each chilled peppermint disc into the melted chocolate. Let any excess chocolate drip off before returning the patty to the parchment-lined baking sheet.
6. Decorate & Set: If you wish, sprinkle your freshly dipped patties with festive sprinkles or crushed candy canes right away. Chill again until the chocolate coating is fully set and firm. Enjoy your delicious homemade treats!