Devonshire clotted cream is a traditional thick cream characterized by its high butterfat content (64%). Clotted cream has been a staple of both Devon and Cornwall for a long time, and it's been a cause for friendly rivalry for as long as anyone can remember.
The product is nowadays made with centrifuges, but in the past full-fat raw cow's milk or cream was first heated in shallow pans, and it was then moved to a cool place so that the thin skimmed milk can sink underneath the thick cream. The watery milk was removed, and the rest was layered in pots, creating clotted cream in the process.