Hake in Green Sauce

Put fish bones or flap and tail in a 2-quart saucepan (set aside steaks or fillets) and add water, onion, parsley sprigs, and one third of garlic, then gently simmer, covered, 20 minutes.

Pour through a fine-mesh or cheesecloth-lined sieve into a small bowl, pressing hard on solids and then discarding them (you will have about 1 cup stock).

Pat fish dry and sprinkle with salt and pepper.

Heat oil and remaining garlic in cazuela over low heat until garlic begins to sizzle.

Add half of minced parsley and all of fish, skin sides up if fillets, then start gently swirling pot, holding onto both handles (it helps to plant your feet apart from each other) so fish moves slowly around edge of bottom of pot and oil laps over it. Cook fish, swirling pot, until bottom 1/2 inch of fish turns white, about 5 minutes. Carefully turn fish over and continue cooking, swirling pot and adding 1 or 2 tablespoons of stock every minute or two, until sauce is emulsified and fish is almost cooked through, about 10 minutes. (You will use about 1/2 cup stock.)

Add peas and remaining minced parsley and cook, swirling pot, until peas are warm and fish is just cooked through, 3 to 5 minutes.

Stock can be made 1 day ahead and cooled completely, uncovered, then chilled, covered. Reheat to warm before using.

*Available at spanishtable.com.