Homemade Crema (Mexican Sour Cream)

Crema is the Mexican version of French crème fraîche. Both are slightly soured and thickened cream, milder and less thick than American sour cream, with crema being the thinnest. The recipe for Lime Chicken with Poblano Sour Cream will have a more authentic touch if made with crema. You can buy crema in Mexican markets or even in some supermarkets, but it’s easy to make it yourself, and the result has a smoother flavor than that of the commercially prepared version.
Use crema as you would sour cream, dolloping or drizzling it on soups, tacos, potatoes, or anything else that needs a little tang. Start with pasteurized cream if you can find it—it makes a richer, thicker crema than ultrapasteurized cream does.

• 1 cup heavy cream (pasteurized or ultrapasteurized)
• 1 Tbs. buttermilk (with active cultures)

In a small saucepan, warm the cream over medium-low heat to about 95ºF, just enough to take off the chill. If it goes over 100ºF, let it cool before continuing.

Stir in the buttermilk and transfer to a clean glass jar. Set the lid loosely on top of the jar—don’t tighten—and let sit in a warm spot, such as near the stove or on top of the fridge, until the cream starts to thicken, 18 to 24 hours. Stir, tighten the lid, and refrigerate until the cream is thicker and thoroughly chilled, 12 to 24 hours more. Stir well before using. The crema should have a thick but pourable consistency.