Preheat the oven to 350°F. Line two muffin tins with 18 paper liners.
Add all cupcake ingredients to the bowl of an electric mixer. Beat well, about 3 minutes, scraping the bowl occasionally.
Divide batter evenly between the lined muffin cups. Bake the cupcakes for 18 to 22 minutes, or until a toothpick inserted in the center comes out clean. Allow the cupcakes to cool, first in the tin for 10 minutes and then on a wire rack for 1 hour.
To Decorate The Cupcakes:
Transfer the frosting to a piping bag with a large round tip. Pipe the frosting in a swirl onto the cooled cupcakes.
Draw a black line around the surface of the frosting using the decorating icing. Stud M&M's vertically into the side of the frosted cupcakes to create a Christmas light effect.