The primary ingredient in tiramisu is mascarpone cheese. This rich and creamy cheese is essential for achieving the luxurious texture and flavor that defines this classic Italian dessert. Tiramisu consists of layers of coffee-soaked ladyfingers, whipped mascarpone, and cocoa powder, creating a delightful combination of flavors and textures. The mascarpone cheese is typically mixed with eggs and sugar to form a smooth filling, which is then layered with the coffee-dipped ladyfingers. The dessert is often chilled before serving, allowing the flavors to meld together beautifully.