From: The Thorough Good Cook

Sauces: 37. Lyonnaise

Slice three onions, place in a little butter with a small piece of ham; when nicely browned, add Spanish sauce, according to the quantity wanted, and a ragout-spoonful of consommé; let it boil; draw it to the corner of the stove to throw up the fat; skim well, and pass it through a tammy; put it into another stew-pan with button onions cut in rings, fried brown, and drained in a cloth; let it boil five minutes. Take off any butter which may rise, and keep your sauce hot in the metal bath. Some call this Sauce Bretonne.