Croûte aux Champignons

Yves Alexander, who was born and raised in Paris, now lives in Strasbourg, where his family’s roots go back to 1760. When he is not on the road for his job as a traveling salesman, he does most of the cooking at home. A virtual oral dictionary of gastronomy and French Jewish history, Yves kindly shepherded me around Alsace, where he showed me extraordinary vestiges of a very long past, which went back in some instances to the Roman legions’ trip over the Alps and through Lugano, perhaps during the Battle of Bibracte, in the winter of 59–58 B.C.E. It was here that Caesar’s army defeated the Helvetii, who were trying to migrate from Switzerland to Aquitaine, in the southwest of France. Like every Frenchman, Yves cooks by the seasons. This autumn dish, which he prepares when cèpes (generally known in the United States by their Italian name, porcini) are in season, can be made any time of the year using whatever mushrooms are available. Serve it as an appetizer, or as a main course over pasta with a salad. You can also use dried morels or dried porcini, soaking them first in warm water for about 30 minutes. Yves warns not to throw away the liquid. “Just filter the liquid, and reduce it to enhance the taste,” he told me. When fresh porcini are hard to find, Yves likes using a mix of St. George’s mushrooms (fairy-ring mushrooms) and young pied-de-mouton mushrooms, a native species that he buys at farmers’ markets or gathers in the forests.