WHITE FISH STOCK

Steps:

• Spread butter over bottom of a 2- to 3-quart heavy saucepan, then add fish bones and heads, onion, parsley stems, lemon juice, and salt. Steam mixture, covered, over moderately high heat, 5 minutes.
• Add wine and water and bring to a boil. Skim froth, then reduce heat to moderate and simmer, uncovered, 25 minutes.
• Pour stock through a fine-mesh sieve into a large bowl, pressing hard on solids and then discarding them.