Line a muffin tin with cupcake liners. Preheat oven according to cake mix’s directions.
Prepare cupcakes according to cake mix’s directions and bake. Allow cupcakes to cool completely before decorating.
As the cupcakes cool, prepare toppings. Cut each regular-sized marshmallow in half, lengthwise. Line up the marshmallow halves on wax paper, bottom side up.
In a large bowl, mix together softened butter, confectioners’ sugar and milk with an electric mixer. Start on low and increase to high. Once all ingredients are well combined and smooth, the buttercream is complete.
Scoop a ¼ cup of the buttercream into a separate bowl and tint with one small drop of pink gel food coloring. Scoop pink buttercream into a piping bag with Wilton tip #5 attached. Frost 3 small circles on the bottom of each marshmallow, followed by a large oval on top.
Scoop the remaining buttercream in a piping bag, with Wilton tip #12 attached and frost each cupcake.
Place one mini marshmallow at the top of each cupcake. Place 2 “bunny feet” on each cupcake. Serve and enjoy!