In France simply – soupe à l'oignon
700 or 1050 g onions, thinly sliced
2 or 4 tablespoons olive oil
50 or 100 g butter
2 cloves garlic, crushed
½ level teaspoon granulated sugar
1.2 or 2.4 litres strong beef stock
Place frying pan on a high heat and add the oil and butter together. When this is very hot, add the onions, garlic and sugar, and keep turning them from time to time until the edges of the onions have turned dark – this will take about 6 minutes. Then reduce the heat to its lowest setting and leave the onions to carry on cooking very slowly for about 30 minutes, by which time the base of the pan will be covered with a rich, nut brown, caramelised film. Make the stock in a saucepan, add the onions and season.
As soon as it all comes up to simmering point, turn down the heat to its lowest setting, then go away and leave it to cook very gently, without a lid, for about 1 hour.
Slices of french bread (as necessary) These can be toasted or fried. I prefer fried as they don't go soggy.
Grated Gruyère or Cheddar cheese - place on top of bread, toast and float on soup.