Soubise Sauce
Ingredients.
Six large Onions.
Half a pint of Milk.
Half a pint of White Sauce.
One gill of Cream.
This entry gives only the ingredient list; the method was assumed knowledge in a professional kitchen of the period. What follows covers the measures and the points on which a soubise actually succeeds or fails.
- A gillOne gill is a quarter of a pint, 5 fl oz in imperial measure (the American gill is 4 fl oz). Half a pint in a British book of this date is 10 fl oz, not the American 8.
- White sauceMost likely a béchamel here — butter and flour cooked to a blond roux, let down with milk and simmered until it no longer tastes of raw flour (some books of the period used stock rather than milk). Half a pint of it is roughly 1 oz butter and 1 oz flour to 10 fl oz milk.
- The onionsSix large onions is roughly 2 to 3 lb trimmed. They are the body of the sauce, not a flavouring, so the finished result should taste sweet and mild rather than sharp.
- Blanch firstStandard practice for soubise is to slice the onions and blanch them briefly in boiling water before stewing, which strips out the harsh sulphurous edge.
- Stew, do not brownThe onions are cooked slowly in the milk with a little butter, covered, until completely soft — 30 to 40 minutes over low heat. Colour taken on the pan bottom will tint the sauce and give it a fried-onion flavour that has no place here.
- Sieve or blendThe Victorian cook pushed the cooked onions through a fine sieve or tammy cloth. A blender followed by a sieve gives a smoother result in a fraction of the time; the sauce should be entirely without threads.
- Cream last, off the boilAdd the gill of cream at the end and warm the sauce through rather than letting it boil again, which dulls the flavour.
- Yield and servingAbout a pint and a half, enough for six to eight. Traditionally served with lamb cutlets, mutton or veal; it is also a classic mask for eggs or brains.
Soubise is named for the Princes de Soubise, the French noble family whose kitchens were among the grandest of the eighteenth century, and the attribution is traditional rather than documented — like béchamel and Mornay, the name honours a patron rather than recording an inventor. In nineteenth-century French practice the term covered both a thick onion purée used as a garnish or lining and, as here, an onion purée let down with béchamel and cream into a pouring sauce. Its appearance in a British "high class cookery" manual reflects how completely the professional English kitchen of the late Victorian period had adopted the French repertoire of mother sauces and their derivatives: the book expects its reader already to have white sauce standing ready, and gives only the additions that turn it into something with a name.