Ingredients: Anchovies, fennel, flour, spices, parsley, marjoram, garlic, lemon juice, vinegar, cream.
Wash three anchovies in vinegar, bone and pound them in a mortar with a teaspoonful of chopped fennel and a pinch of cinnamon. Then mix in a teaspoonful of chopped parsley and marjoram, a squeeze of lemon juice, a teaspoonful of flour, half a gill of boiled cream and the bones of the fish for which you will use this sauce. Pass through a sieve, add a clove of garlic with a cut in it, and boil. If the fish you are using is cooked in the oven, add a little of the liquor in which it has been cooked to the sauce. Take out the garlic before serving. Instead of anchovies you may use caviar, pickled tunny, or any other pickled fish.
See also: Wikipedia Cookbook.
Source: ''The Cook's Decameron: A Study In Taste, Containing Over Two Hundred Recipes For Italian Dishes'' from a project that puts out-of-copyright texts into the public domain. This is from a *very* old source, and reflects the cooking at the turn of the last century. Update as necessary.