Clotted cream is a thick, rich dairy product made by gently heating full-fat, unpasteurized cow's milk in shallow pans; as it heats, a dense layer of cream rises to the surface and forms a "clot," concentrating the butterfat into a texture closer to a soft spread than a pourable cream. It's strongly associated with the West Country of England, particularly Devon and Cornwall, whose milk is prized for its high butterfat content.
Clotted cream is the traditional partner to scones and jam in a British cream tea, and it also appears in trifles, shortbread, and ice cream. It differs from whipped cream and crème fraîche in both process and texture: it isn't whipped or cultured, and its high fat content (typically well above 55%) gives it a much denser, spreadable consistency.
South Asian desserts like kulfi and rasmalai use a comparable slow-reduced milk cream called malai, though it's made differently and isn't the same product as English clotted cream.