Bake the cupcakes according to the box directions.

Transfer to wire racks to cool.

Cream the butter in a medium bowl. Slowly add in the powdered sugar, and milk as needed, until everything is incorporated and frosting is the right consistency.

Divide the frosting into equal size batches of the number of colors desired and add several drops of color to each.

Transfer the icing to a piping bag or to a zippered bag and clip the corner.

Pipe icing onto cupcakes and top with Peeps.

You can also add sugar sprinkles if desired.