The perfect example of how an ingredient as humble as the onion can be transformed into a first-rate dish with just a little patience and a low flame.
Ingredients:
- 5 large onions
- 1 litre of beef stock (or a strong chicken stock)
- 50 g of butter
- 1 tablespoon of flour
- Slices of toasted rustic bread
- Grated Gruyère or Emmental cheese (plenty)
- Olive oil, salt and pepper
Preparation:
- Cut the onions into thin julienne strips (long strips).
- In a large pot, heat the butter with a splash of oil (so the butter doesn’t burn). Add the onion and sweat it over very low heat for about 35-45 minutes. Stir from time to time; it should end up very tender, reduced and a dark toasted colour, but without burning.
- Add the tablespoon of flour, stir well and cook for a couple of minutes to remove the raw taste.
- Gradually pour in the hot stock, season with salt and pepper to taste and simmer over low heat for another 20 minutes so that all the flavours blend well.
- Serve the soup in individual ovenproof bowls. Place one or two slices of toasted bread floating on the surface, cover them with a mountain of grated cheese and gratinate in the oven at 220ºC until melted and golden.
