Crème de Cerfeuil Bulbeux, otherwise Chevreuse

Crème de Cerfeuil Bulbeux, ou Chevreuse (cream of tuberous-root chervil), teaches the quiet discipline behind every pale cream soup: coax out flavor without taking color. The root has the sweetness of chestnut and a faint herbal perfume. Brown it and you exchange that delicacy for roast flavor, pleasant enough, but no longer Chevreuse.

The original entry assumed a saucier, prepared Béchamel, white consommé never far from the fire, a tammy cloth, and enough hands to cut separate chicken and truffle juliennes. At home, a heavy saucepan does the saucier's work, while a blender followed by a fine-mesh sieve replaces the tammy. I have retained the source ratio of one pound of root to one and one-quarter imperial pints of Béchamel, then measured the sufficient consommé as a practical range because each batch of roots carries a different amount of starch. The separate sauce and garnish stations are brigade scaffolding and can go. The butter stew, slow cooking in Béchamel, sieving, and last-minute cream finish are the dish, so they stay.

Finished properly, Chevreuse is ivory and satin-smooth, fluid enough to leave the ladle in one broad ribbon, with fine threads of chicken and black truffle appearing through the pale soup. Before the roots meet the pan, settle the heat low and keep it there. They must soften in butter without acquiring even a brown edge.