Filets de Soles aux Champignons

Filets de Soles aux Champignons (sole fillets with mushrooms) teaches a principle worth carrying through the whole classical repertoire: the mushroom liquor is not a by-product. It poaches the fish, collects the sole's juices, reduces to an essence, and becomes the foundation of the sauce. Discard it or weaken it, and the dish has nowhere to go.

The brigade version assumed a saucier on staff, prepared velouté beside a stockpot never off the fire, and mushroom cuisson already waiting. A salamander has no job here because nothing is browned or gratinéed. For one cook, one stove, one evening, the honest equivalent is to make the mushroom liquor in the same covered pan, measure two tablespoons of prepared fish velouté, and use a warm oval platter while that pan becomes the saucier. Separate holding pans are scaffolding and can go. Stewing the mushrooms, poaching the folded fillets in their liquor, reducing that liquor to one-third, and mounting the sauce with butter are the dish, and every one stays.

The finished sole should be tender enough to separate beneath a fork, with small mushrooms gathered at the center and a pale sauce that coats rather than buries. Measure the mushroom liquor before the fish goes in, then reduce the poaching liquor to one-third; that is the step that decides the sauce.