Lime-Cilantro Butter

The pairing of lime and cilantro is commonplace—probably because it is so good. It’s imperative that you use both the zest and juice of the lime, or else the mixture will be too tart and the flavor of the cilantro will dominate. We call for unsalted butter to control the salt level, but if all you have is salted butter, just eliminate the salt in the recipe and the flavor will be fine. You can make the sauce ahead, but it will have to be reheated just before serving.