Cheese curds, a delicacy to many, are the basis of all blocks and slices of cheddar cheese. Basically leftovers of the cheese making process, curds are so popular as a side dish they have their own national day — October 15th — a day conveniently created in 2015 by Culver’s, which sells nearly a billion curds per year. Culver’s Director of Menu Development, Quinn Adkins, says the chain’s Twitter account posted a fake menu addition for April Fool’s Day: the Curderburger. He tells WGN’s Steve Alexander so many customers demanded it be real, they made it so. It’s the basic Culver’s Butterburger topped with a crown of curds.