Every household needs a back-pocket green sauce to instantly zhuzh up a simply prepared protein—or even leftovers. This velvety rendition of chimichurri combines the sharp acidity and herbaceous vibrance of the original with the mellow tang of yogurt for a good-with-everything sauce. Thanks to the tenderizing effect of the yogurt, the sauce can perform double duty: as a marinade for meat, like here, and as a condiment in its own right. In lieu of chicken, serve the sauce with meatballs, zucchini fritters, roasted mushrooms, or a turkey burger.