Pound in a mortar, and make into a smooth, fine paste, one ounce of pistachios and one ounce of fir-apple kernels, or, if these are not available, one ounce of sweet almonds; add half a tablespoonful of cold Bechamel. Put paste into a bowl, add the yolks of six eggs, a little salt and pepper, and finish the sauce with one quart of oil, the juice of one lemon, and proceed as for Mayonnaise.

Complete with three tablespoonfuls of puree of herbs, prepared with equal quantities of chervil, parsley, tarragon, and fresh pimpernel, previously blanched. Cool quickly, expel the water, and pass through a fine sieve.

Serve with cold fish.