Line a tray or baking sheet with parchment paper.
Cut each mini marshmallow in half so you have 12 small pieces for Santa’s hat pom-poms.
Roughly chop the white chocolate. Melt it gently in a double boiler or microwave it in 15–20 second intervals, stirring between each one, until completely smooth.
Dip the bottom half of each cookie into the melted white chocolate, leaving a strip in the center uncovered for Santa’s face.
Place the cookies on the prepared tray. While the white chocolate is still soft, press one red chocolate candy into the center of each cookie to make the nose.
Let the cookies sit until the white chocolate begins to set.
Melt the red candy melts according to the package directions.
Dip the top portion of each cookie into the red coating, leaving the face area uncovered to create Santa’s hat.
Before the red coating sets, gently press half a mini marshmallow onto one side of each hat for the pom-pom.
Let the cookies cool completely until both coatings are fully set.
Add two small dots of black decorating icing for Santa’s eyes.
Let the icing dry completely before moving or storing the cookies.