The Reese's Big Cup is the traditional peanut butter cup in a single big version.
H.B. Reese worked as a dairy farmer. During his work at chocolate company Hershey's he decided to start his own candy business on the side, called Reese's. His Peanuter Butter Cups have gotten world famous. They were so popular, that Reese's old employer, Hershey's, bought the marketing- and production rights from him.