Ingredients

　　1 pound bones and trimmings of any white fish such as sole, flounder, or whiting, chopped

　　1 cup sliced onion

　　12 long parsley sprigs

　　2 tablespoons fresh lemon juice, or to taste

　　1/2 teaspoon salt

　　1/2 cup dry white wine

　　In a well-buttered heavy saucepan combine the fish bones and trimmings, the onion, the parsley, the lemon juice, and the salt and steam the mixture, covered, over moderately high heat for 5 minutes. Add 3 1/2 cups cold water and the wine, bring the liquid to a boil, skimming the froth, and simmer the stock for 20 minutes. Strain the stock through a fine sieve into a bowl, let it cool to warm, and chill it, covered. The stock keeps, covered and chilled, for 1 week if it is brought to a boil every 2 days and then allowed to cool to warm, uncovered, before being chilled again, and keeps, frozen, for 3 months.