By Jane Grigson
Visitors to Normandy are likely to flash through Isigny on their way to Bayeux without stopping to recall that it produces some of France’s finest butter. Its only rival, I suppose, is the town of Echiré in the Deux-Sèvres. Sauce Isigny is more usually known as hollandaise sauce, but I suspect that its original home was Paris, and not Isigny or Holland at all. Nevertheless, it goes so well with Normandy food - fish of many kinds, artichokes, poultry - that it cannot be left out.