Zesty herb sauce

To give this parsley-cilantro sauce more body and a little creaminess, we puree shallots with water until thick, then add a little Dijon mustard to help emulsify the ingredients. Not only do these additions enhance the texture, but they also add savory depth to the sauce. Serve at room temperature over fish or chicken, baked or roasted potatoes, or steamed or roasted vegetables. Though leftovers will hold up, flavor-wise, for two or three days, the herbs will start to discolor—so the sauce is best enjoyed within a few hours of making.