Cover the bottom of a marshmallow with frosting and place towards the back of the cupcake. If there is a gap where the marshmallow meets the top of the cupcake, fill the gap in with frosting. You want it to look like it’s melting into the top of the cupcake.
Shape fondant into small carrot shapes to form the snowman's nose. Dab a small bit of frosting on the back end of the carrot nose and gently press it onto the center of the marshmallow. Hold the nose in place for a minute to allow it to start to dry and stick. Add a little extra frosting around the carrot nose if needed to help secure it in place.
Using black icing, add 2 dots for the snowman's eyes and a series of dots to become the snowman's mouth. Then, draw arms and hands coming out from the bottom sides of the marshmallow.
Gently place 3 confetti sprinkles of the same color down the front of the cupcake, in between the snowman's arms. These will act as the snowman's buttons.