Should cupcakes have frosting?

I got into a debate with my fellow cupcake researchers about whether or not frosting was a requirement for cupcakes. The bakery we were at had a gluten-free option, but the cupcake didn’t have frosting on top. In fact, it had nothing. My first thought was to include it in the guide, but then I wondered if it really met the definition.

Admittedly, some places have alternate toppings on their cupcakes. More has a lemon cupcake that’s topped with meringue, and Sprinkles has a cinnamon sugar cupcake that’s sans frosting. Are these technically cupcakes? Or are they just tasty dessert impostors?

My feeling is frosting is a must, but I agreed to settle it here. What do you think? Is frosting a requirement for your cupcake?