Green Spanish Sauce

Pound to a paste one ounce of chervil and one ounce of parsley; add to it four ounces of bread-crumbs soaked in water and then squeezed out, six anchovy fillets, two ounces of chopped pickled gherkins, two ounces of capers, and one small chopped up onion; pound well the whole and then rub it through a sieve into a bowl, beat it well with some sweet oil, the same as for a mayonnaise, adding salt, pepper, and spinach green to color; soften the sauce with a little water.