Mexican crema is a type of Mexican cultured cream that has a slightly tangy flavor. You can use sour cream as a substitute for Mexican crema in most recipes. While the flavors and textures might be slightly different, sour cream will still provide a creamy and tangy element to your dish. If you want to make it more similar to Mexican crema, try thinning the sour cream with a little milk or lime juice and adding a pinch of salt.