Crayfish or Lobster Coulis for Quenelles

By James MacGuire

The classic French crayfish sauce, sauce Nantua, a frequent companion to quenelles, is a béchamel finished with crayfish butter and cream. It can be improved by substituting a white-wine sauce for the béchamel, but the flavors remain timid, and the traditional crayfish butter — cooked crayfish shells puréed with butter and simmered for a long time, then…