Julia Child, from Mastering the Art of French Cooking, vol. 1
There are recipes for beurre blanc all over the Internet, but we thought Julia Child's classic recipe is worth having.
1/4 cup white wine vinegar
1/4 cup dry white wine or lemon juice
1 tablespoon very finely minced shallots or green onions
1/4 tsp salt
1/8 tsp white pepper
A wire whip
12 ounces (3 sticks) best quality, chilled unsalted butter cut into 24 pieces (Ed. Note: if you have only salted butter, do not add extra salt.)
Salt and pepper
In a medium saucepan, boil the liquids, shallots or onions, and seasonings until they have reduced to about I ½ tablespoons.
Remove saucepan from heat and immediately beat in 2 pieces of chilled butter. As the butter softens and creams in the liquid, beat in another piece. Then set the saucepan over very low heat and, beating constantly, continue adding successive pieces of butter as each previous piece has almost creamed into the sauce. The sauce will be thick and ivory-colored, the consistency of a light hollandaise. Immediately remove from heat as soon as all the butter has been used. Beat in additional seasonings to taste.
Transfer the sauce to a barely warmed bowl, and serve.
Makes 1½ cups (Ed. Note: does not reheat but is delicious as a compound butter.)
Holding the Sauce
Beurre blanc will thin out and turn oily almost at once if it is reheated or if it is kept over hot water. It must be held over water of a barely tepid temperature, just warm enough to keep the butter from congealing. Or place the sauce near the very faint heat of a gas pilot light.