Make your favorite sugar cookie recipe, or use a sugar cookie mix. Roll them into balls, and bake into circle cookies. Let cool completely.
While the cookies are baking, make the buttercream frosting. Beat together the butter and vanilla, then slowly beat in the powdered sugar. Add enough milk to get the right frosting consistency. Beat well. Mix in a dash of salt.
Decorating your cookies...
After frosting each cookie, use the black piping icing to make small loops across the top. Add M&Ms (all the colors except brown) where the loops intersect, or where they loop around.