Using a stand or hand mixer, beat butter on medium speed until it is smooth.
Add the full jar of marshmallow and continue mixing.
Slowly add the orange soda.
Add powdered sugar 1/4 cup at a minute.
Beat at medium speed for 3-4 minutes.
If desired, add a few drops of orange food coloring.
Fold the frosting to get swirls of the orange color.
Place the frosting in a piping bag and pipe onto the cupcakes.