In a large bowl, combine powdered sugar and cocoa powder.

Add softened butter, peppermint extract, and 3 tablespoons milk.

Mix until smooth and dough-like. Add more milk if needed.

Scoop about 1 tablespoon of the mixture.

Roll into a ball, then flatten into a round disc.

Arrange on parchment-lined tray.

Chill for 30 minutes.

Melt the semi-sweet chocolate in the microwave (30-second bursts) or over a double boiler.

Dip each patty into the melted chocolate, covering completely.

Place back on parchment paper.

Let patties set at room temperature or refrigerate until firm.

Enjoy immediately or store in an airtight container.