Mascarpone is a soft, high-fat Italian cream cheese made by heating cream and curdling it with an acid, such as citric or tartaric acid, rather than with rennet. It originated in the Lombardy region of northern Italy and has a mild, slightly sweet, very rich flavor with a texture similar to a thick, spreadable cream cheese or crème fraîche. Mascarpone is the key ingredient in tiramisu and is also used in cheesecakes, pasta sauces, and risottos; because it is not rennet-set, it has a softer texture and higher fat content than standard cream cheese.