Slice four large onions thinly. Melt 1oz butter plus a bit of olive oil in a pan, add the onions and fry slowly. If it’s a cast-iron pan, turn the heat up gradually until the onions caramelise. In a normal saucepan, add half a tablespoon of white sugar to help the onions caramelise. Then pour in 1.75 pints water, a stock cube and a dash of vinegar. Simmer for a quarter of an hour then season to taste.

Jocasta Innes: The Pauper’s Cookbook, page 120