Cheesecake is a sweet dessert consisting of one or more layers. The main, and thickest, layer consists of a mixture of a soft, fresh cheese (typically cottage cheese, cream cheese or ricotta), eggs, and sugar. If there is a bottom layer, it most often consists of a crust or base made from crushed cookies (or digestive biscuits), graham crackers, pastry, or sometimes sponge cake. Cheesecake may be baked or unbaked (and is usually refrigerated).
Cheesecake is usually sweetened with sugar and may be flavored in different ways. Vanilla, spices, lemon, chocolate, pumpkin, or other flavors may be added to the main cheese layer. Additional flavors and visual appeal may be added by topping the finished dessert with fruit, whipped cream, nuts, cookies, fruit sauce, chocolate syrup, or other ingredients.
An ancient form of cheesecake may have been a popular dish in ancient Greece even prior to Romans' adoption of it with the conquest of Greece. The earliest attested mention of a cheesecake is by the Greek physician Aegimus (5th century BCE), who wrote a book on the art of making cheesecakes (πλακουντοποιικόν σύγγραμμα—plakountopoiikon sungramma). The earliest extant cheesecake recipes are found in Cato the Elder's De Agri Cultura, which includes recipes for three cakes for religious uses: libum, savillum and placenta. Of the three, placenta cake is the most like modern cheesecakes: having a crust that is separately prepared and baked.
A more modern version called a sambocade, made with elderflower and rose water, is found in Forme of Cury, an English cookbook from 1390. On this basis, chef Heston Blumenthal has argued that cheesecake is an English invention.