Serves 4
1 lb (450g) onions
1 oz (25g) butter
2 pints (1.1 litres) chicken stock salt and freshly milled pepper
1 oz (25g) cornflour
4 tablespoons cold water
Garnish
4 slices day-old French bread butter, for spreading
2 oz (50g) grated hard cheese
Peel and finely slice the onions. Melt the butter in a large saucepan over low heat, add the onions and toss them in the butter. Cover with a pan lid and cook gently for about 30-40 minutes so that the onions stew in their own juices and are soft and translucent Remove the pan lid and cook the onions briskly, stirring occasionally, until lightly browned.
Add the stock and season with salt and plenty of pepper. Simmer gently, uncovered, for 20-30 minutes. Blend the cornflour with the cold water and stir into the soup, then bring to the boil stirring all the time, until soup thickens. Simmer gently for 2-3 minutes, stirring, and check seasoning.
Toast the bread on one side under a hot grill. Remove from the grill and spread each slice with a little butter and sprinkle over a little grated cheese, then grill until bread is crisp and cheese is melted. Put 1 teaspoon grated cheese into four warmed soup bowls. Ladle in the hot soup and float the cheese bread on top. This soup is filling enough to serve as a lunch or supper dish. Or serve as a first course for 6, in which case use 6 slices of bread.