Trout in Parchment with Crosnes, Fennel, Carrots, and Herbs

Odessa says that this is a March dish, because it uses the last of the root-cellar vegetables—in this case, crosnes. Crosnes look and taste like a bit of a cross between a Jerusalem artichoke and a small fingerling potato, despite the fact that they belong botanically to the mint family. They are very popular in France. If you can’t find them here, substitute slices of Jerusalem artichoke.

The trout Odessa uses at her restaurant, Etoile, in M