Bake cupcakes according to box mix recipe, or from scratch recipe instructions. Let them cool at least 1-2 hours. Prepare frosting if from scratch recipe, or use from container if you have one that is allergen friendly for you.
You can leave the frosting as is, or you can alternately sprinkle flaked coconut on immediately after frosting, and just before adding the ears.
I would recommend working quickly and one cupcake at a time, otherwise the frosting sets and the coconut and/or ears won't stick and hold.
For the ears, just cut the marshmallow in half, and then dip the sticky side into sprinkles before placing as ears.
You can use a box mix that is friendly for you such as King Arthur brand, Cherrybrook Kitchen, and others. There are several on the market in traditional grocery stores, and even more in specialty stores such as Sprouts and Whole Foods.
Alternately, I have a recipe linked in the blog post for this recipe that directs you to two allergy friendly recipes. One is a spice cake cupcake, and the other is a chocolate cake cupcake, both with allergy friendly gluten free and vegan frosting.
For the frosting Pillsbury is top 8 free except soy, Betty Crocker is top 8 free except milk, or alternately use the recipes I have listed above.