In a large bowl, mix together butter, powdered sugar and peppermint extract until it is fully combined. Roll the mixture into balls and place onto a plate. Freeze for at least 20 minutes.
Place chocolate chips into a microwave-safe bowl, and heat in the microwave in 30-second intervals, stirring well until it is fully melted and smooth. Coat each truffle in the chocolate and set onto a plate. Let sit until it is completely set.