In a large bowl, mix butter with powdered sugar and vanilla extract until combined. Roll the mixture into balls, and set onto a large plate. Refrigerate for at least 20 minutes.
Place the chocolate chips into a microwave-safe bowl. Heat in the microwave in 30-second intervals, stirring well until it is fully melted and smooth.
Fully coat each buttercream truffle into the melted chocolate. Set back onto a plate, and let sit until the chocolate has completely set.