Breton
The Celts of Brittany have immortalised themselves and their mutton by means of a few onions and haricot beans. In the first place they have invented the Breton sauce. It is the counterpart of Soubise, only that the one is brown, the other white. When these noble Bretons eat roast mutton they make a quantity of their lovely brown sauce, they boil about an equal quantity of white haricot beans, they mix the two together for a garnish, and there is the Gigot à la Bretonne. To be exact, let us say that there are two pints of garnish :-one pint should be the brown purée of onions, the other pint white haricots nestling in the brown.
Breton Sauce is to Soubise what brown is to white. Peel, trim, and mince a good quantity of onions-no stint.
Pass them in butter with a little salt, perhaps also some sugar, till they are of a rich red colour, and then set them to stew in their own juice with a faggot of sweet herbs. When they are done, take out the faggot and add a brown sauce to them-the best is not too good. The books direct that after this the onions and the sauce together should be reduced to a glaze, which is quite unnecessary. The object is to develop the roast flavour of the onions, which is developed enough if they have been fried enough at first. Pass all through a tammy, and finish it with a piece of butter and a squeeze of lemon.
Kettner gives a method rather than a formula, so the quantities need pinning down. The one number he does supply is the ratio: equal volumes of onion purée and cooked white beans, two pints of garnish in all for a leg of lamb.
- The hinge: colour before liquidEverything depends on cooking the onions in butter until they are genuinely deep brown — what he calls \"a rich red colour\" — before any stewing or sauce goes in. That is where the roast flavour comes from, and it takes 40 minutes to an hour over moderate heat, not ten. If they are merely golden the finished sauce will taste flat, and no amount of reducing later will fix it.
- QuantitiesKettner gives no weights. Roughly 2 lb of onions, sliced thin, will cook down to something like a pint of purée once the sauce is in; pair it with about 6–7 oz dried white haricots (soaked overnight and simmered until tender), which will swell to about a pint. Kettner's pints are imperial, 20 fl oz, so his two pints are about 2.4 US pints.
- Brown sauceIn 1877 this would most likely mean espagnole or demi-glace, a roux-thickened brown stock, and "the best is not too good" is his way of saying do not economise here. A well-reduced veal or lamb stock, lightly thickened, does the job; add it a little at a time, keeping in mind that the finished onion purée is only meant to make up one of his two pints.
- Faggot of sweet herbsA bouquet garni: parsley stalks, thyme and a bay leaf tied together so it can be lifted out whole. Tie it with string rather than fishing for the pieces later.
- TammyA tammy was a worsted cloth through which sauce was wrung by two people twisting the ends. A fine conical strainer pressed with a ladle, or a blitz in a blender followed by a sieve, gives the same smooth purée with less laundry.
- Haricot beansDried white beans — cannellini, navy or the Breton coco de Paimpol if you can get them. Canned beans work but should be drained, rinsed and folded in at the last moment; they break up if stirred into hot sauce for long.
- MuttonMutton means an older sheep — usually reckoned over a year old, sometimes over two — stronger-flavoured and now sold mainly by specialist butchers. A leg of lamb roasted to your preference is the usual substitute, and the sauce suits it well.
- On skipping the glazeKettner is right that reducing the onions and sauce to a glaze is unnecessary, but the purée should still be thick enough to hold the beans rather than run off the plate. Finish off the heat with a knob of butter and a squeeze of lemon, and taste for salt — a reduced brown sauce can carry more than you expect.
Kettner's Book of the Table (1877, generally credited to E. S. Dallas rather than the restaurateur Auguste Kettner himself) works through the French repertoire alphabetically and in an opinionated voice, which is why an entry on a sauce turns into an argument with "the books" about whether to reduce it to a glaze. À la bretonne in classical French cookery signals white haricot beans, and Brittany's association with the bean is long-standing, though the haricot itself is a New World plant that reached Europe only in the sixteenth century. The pairing of lamb or mutton with beans and onions is peasant logic dressed up for the restaurant — the same instinct that produced cassoulet further south. Soubise, the white onion purée Kettner uses as his reference point, is traditionally named for the eighteenth-century Prince de Soubise, though the attribution is customary rather than documented; the brown version here simply pushes the same onions much further in the pan.