BEURRE BLANC-BEURRE NANTAIS [White Butter Sauce]
For: boiled fish originally, but now for all kinds of fish and shellfish, and vegetables such as asparagus, broccoli, cauliflower, as well as for sautés of veal, chicken, kidneys, livers, and so forth.
This famous sauce originated in Nantes, on the Loire River, and is traditionally served with pike, brochet au beurre blanc. Warm, thick, creamy, and butter-colored, the original sauce is only butter creamed with shallots, wine vinegar, lemon, and seasonings. The idea was taken up by nouvelle cuisine chefs in the early seventies because it is a far easier sauce system than the long-simmered classics, and it is delicious with so many dishes. Rather than a lemon and vinegar base, you use a strong reduction of fish or meat juices—the residue, for instance, of sautéed chicken livers or foie gras deglazed with wine and shallots and, perhaps, a dash of wine vinegar all reduced almost to a syrup; this is then enriched by the beating in of a large quantity of butter. It is, in fact, the usual buttered deglazing sauce, but rather than beating in 2 or 3 tablespoons of butter for 4 to 6 servings, you might add as much as half a pound. With butter at 100 calories per tablespoon, an otherwise simple sauté can be marvelously yet astronomically (even lethally) fattening; but, as we imply in most of our recipes, “the amount of butter is up to you.”
The trick in making a beurre blanc is to prevent the butter from turning oily like melted butter; it must retain its warm, thick, creamy consistency. A chemical process takes place once the base is boiled down and the acids are well concentrated so that the milk solids remain in suspension rather than sinking to the bottom of the pan. We give two methods here, first the classic way where the butter is slowly creamed in, and second the newer fast-boil system. In either case you may beat in more butter than the amount given, but if you beat in less you may have too acid-tasting a sauce.