Black Cod with Mushrooms and Sansho Pepper

Ingredients

• 36 ounce filets black with skin
• 7 ounces enoki mushrooms fresh cut into 3-inch lengths and spongy base discarded
• 3  garlic clove divided thinly sliced
• 0.1 teaspoon pepper whole for sprinkling, or 1 teaspoon sichuan peppercorns (sometimes labeled "sansyo")
• 6 tablespoons soy sauce reduced-sodium
• 2 tablespoons rice wine sweet (Japanese rice wine)
• 5 ounces mushrooms fresh (sometimes called beech mushrooms)
• 6 servings spring onion thinly sliced
• 1  shallots sliced
• 1 teaspoon vegetable oil 
• 1 cup water 

Equipment

• bowl
• frying pan
• sauce pan
• sieve

Directions

1. Bring water, soy sauce, mirin, sansho pepper, shallot, and one third of garlic to a boil in a 1- to 2-quart heavy saucepan, then simmer 5 minutes.
2. Let broth stand off heat 10 minutes.
3. Cook remaining garlic in oil in a 10-inch heavy skillet over medium heat, stirring, until just golden.
4. Add all mushrooms and cook, stirring occasionally, until tender, about 3 minutes.
5. Strain broth through a fine-mesh sieve into mushroom mixture, discarding solids, and simmer 1 minute.
6. Pat fish dry and sprinkle with 1/2 teaspoon salt and 1/4 teaspoon pepper.
7. Heat oil in a 12-inch heavy nonstick skillet over medium-high heat until hot, then sauté fish, skin side down, turning once, until golden brown, just starting to flake, and just cooked through, about 10 minutes.
8. Transfer fish to shallow bowls. Reheat broth and divide among bowls, then sprinkle very lightly with more sansho pepper (if using).
9. Broth can be made 1 day ahead and chilled, covered (once cool). Gently reheat before using.