Ingredients:

  Amount  Measure       Ingredient -- Preparation Method
--------  ------------  --------------------------------
   1      large         onion -- thinly sliced
   1      tablespoon    oil
   1 1/2  cups          mushrooms -- sliced thinly
   1      pound         fish fillets; -- (cod, halibut
                        cut into 1" slices
   1      dash          Salt
   1      dash          Pepper
   1      stalk         celery, sliced thin
   1      tablespoon    soy sauce
   1      tablespoon    dry sherry

Preparation:

Preheat skillet(non-stick) and sauté onion in oil. Add mushrooms and sauté about 2 minutes, stirring constantly, until mushrooms wilt. Spread half of fillet slices on mushrooms; sprinkle with salt and pepper; and remaining fillet; sprinkle these with salt and pepper. Add celery, soy sauce, and sherry; cook gently, covered, for ten minutes.