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Onions, Coloured, for Soup Flavouring
Put into an oven half a dozen large onions on a tin dish, with equal quantities of butter and sugar (previously well mixed together) on the top of each. As the mixture dissolves, baste the onions frequently with it; they must not get dry, but they should be black through, yet not burnt. A slow oven is required. For imparting a flavour and colour to soups black onions are very valuable. Probable cost, 1 1/2d. per pound.
A larder preparation rather than a dish: onions baked to a deep mahogany-black in butter and sugar, kept on hand to colour and sweeten stocks and brown soups. The whole thing turns on the distinction between dark and burnt.
- Oven temperature"A slow oven" is usually taken to mean somewhere around 275-300F/140-150C, and lower is safer than higher here: too hot and the sugar scorches before the onion has softened through, and scorched sugar is bitter rather than sweet.
- The hinge: black but not burntThe colour should come from long caramelisation of the onion's own sugars plus the added sugar, not from carbon. Taste a sliver before you stop: it should be sweet, sticky and faintly bitter at most. Any acrid edge means the batch will make every soup it touches taste of ash.
- Butter and sugar quantitiesThe original gives none. About a tablespoon each per large onion, creamed together, is a workable starting point; it needs to be enough to keep basting liquid in the dish for two hours or more.
- TimingExpect 2 to 3 hours for six large onions, basting every 20 minutes or so. Peel them but leave them whole and root-end intact so they hold their shape while the sugar works.
- Don't let it dry out"They must not get dry" is the practical warning. If the pan looks like it is running out of liquid, add a spoonful of water rather than more butter, and cover loosely with foil for the last stretch.
- The tin dishA thin tin sheet under direct oven heat will burn the syrup. Use a heavy roasting tin or a shallow enamelled dish, and stir the syrup up from the base each time you baste.
- Yield and useSix onions gives enough to season a good many pots of soup. Reckon roughly a quarter to half an onion, mashed with a little of the pan syrup, per quart of stock, added at the end and tasted as you go. Refrigerated in a sealed jar with its syrup they keep about a week; they freeze well in portions.
- Old money"1 1/2d. per pound" is one and a half old pence, from a currency of 240 pence to the pound sterling. It is a note on how cheap onions were, not a figure that converts usefully.
Browned onion was the Victorian kitchen's honest answer to a problem it otherwise solved with dubious commercial colourings: brown soups and gravies were expected to be brown, and a stock made without a joint of well-roasted meat comes out pale. It is of a piece with the caramel (burnt sugar) and browning colourings found elsewhere in the same books, but better flavoured than either. The technique is the same chemistry that underlies French onion soup and the long-cooked onions of Indian and Persian cooking, the slow breakdown of the onion's sugars and sulphur compounds into sweetness and depth; adding butter and sugar simply speeds and deepens it. Bottled gravy brownings eventually made the practice look old-fashioned, but a jar of black onions will still do more for a thin stock than any of them.