Sell sizes other than “huge”.
There are a ton of vendors at this thing. And it’s a festival about ice cream. Wouldn’t you want people to be able to try as many different options as possible?
Offer inexpensive “tasting” sizes so people can sample more of your flavors.
Sure, you can continue to serve up enormous mounds of ice cream in giant cups for people who want that. But give those of us who want to try more than one thing an option too. Please?