Crème fraîche is the perfect rich, creamy, and tangy addition to mashed potatoes, vegetable soup, cake frosting, and more. However, this trendy condiment can be expensive and difficult to find, making it more cost-effective to make it at home, and one recipe for crème fraîche calls for just two ingredients and almost no effort.

Crème fraîche is simply cream that is thickened through a quick and easy fermentation process, and Serious Eats says you can pull it off using buttermilk. The bacteria naturally present in buttermilk inoculates and cultures the pasteurized heavy cream over the course of 12 to 36 hours to make a creamy final product.

To make crème fraîche, all you have to do is mix a cup of heavy cream with 2 tablespoons of buttermilk, cover the container with cheesecloth or a tea towel, and leave it in a warm-ish spot out of direct sunlight for at least 12 hours. Once the crème fraîche is set, you can cover it and store it in the fridge for up to a week.