or 1 parts heavy cream

Heavy cream, also known as heavy whipping cream or double cream (in British English), is the high-fat portion of milk that naturally rises to the surface during separation. Consisting of milk fat (36-40% fat content in the United States, 48% in the United Kingdom), heavy cream is a dairy product derived from bovine milk. The cream separates due to the lower density of fat globules compared to the milk's aqueous components. It has a pale ivory color, rich mouthfeel, and mild dairy flavor that intensifies when heated or whipped.

Heavy cream is distinct from light cream (18-30% fat) and half-and-half (10-18% fat) due to its higher fat content, which enables it to whip into stiff peaks and provides superior emulsifying and thickening properties in cooking.

Heavy cream is fundamental in both sweet and savory cooking across numerous cuisines. It is whipped into stabilized foams for desserts, folded into mousses and soufflés, and used as a base for custards and crème anglaise. In savory applications, it enriches sauces (particularly French beurre blanc and pan reductions), soups, and risottos, while also serving as a key component in butter-making through fermentation or churning. Heavy cream is indispensable in pastry work for fillings, toppings, and ganaches, and is used to finish pasta dishes in Italian cuisine. Its high fat content makes it ideal for creating emulsions and adding richness and body to dishes without altering flavor profiles significantly.