Cheesecake is broadly categorized into baked and unbaked types.
A baked cheesecake is set by heat, usually with eggs helping create a firm but creamy custard-like filling. An unbaked cheesecake is set without baking, commonly through refrigeration, whipped cream, gelatin, or another thickening method. Both styles may have a biscuit, pastry, sponge, or no crust at all.
The distinction is about preparation rather than one universal recipe. New York-style cheesecake is a familiar baked example, while many British-style and South African-style cheesecakes are chilled and unbaked. Japanese “rare cheesecake” is also a Japanese term for a no-bake cheesecake, not a rare or unusual flavor.
Cheesecake is older than its modern cream-cheese form. Ancient Greek recipes described cheese-based cakes, and Roman writers recorded related preparations. The modern English word appeared by the 15th century, while cheesecake developed toward its current form around the 18th century. Despite its name, it is sometimes classified as a custard pie, tart, flan, or torte rather than a conventional cake.