French onion soup or “soup a l’oignon” is one of the oldest recipes in the vast culinary tradition of France. Its base is an abundant amount of caramelized onion, served on a slice of bread and with gratin cheese on top. This soup is said to have become extremely popular in the 19th century as it was served in Parisian taverns around Les Halles throughout the day, and even late at night.
Ingredients:
1 kg of onion
600 ml of meat broth
250 gr of Emmental cheese
Some slices of bread from the previous day
Salt, pepper, extra virgin olive oil and/or butter
To prepare the meat broth, boil some beef bones for 40 minutes together with various vegetables, depending on availability (onion, carrot, celery, leek, turnip, etc.). Take care to remove the foam that will appear on the surface when the broth comes to a boil. When finished, strain and reserve.
Meanwhile, cut the onions into julienne and heat a little extra virgin olive oil and/or butter in another pot. Saute the onions over low heat, stirring occasionally to make sure they don’t stick or burn. Salt lightly to help them release liquid, this will also help prevent them from burning. The objective is to caramelize them to extract the maximum of flavor.
After about half an hour, the onions will have reduced noticeably, while at the same time they will have taken on a brown color.
Then add the strained broth and boil over low heat for an additional 20 minutes.
In parallel, preheat the oven to 180 degrees. Toast a slice of bread per guest for a few minutes.
When the soup is ready, place a slice of bread in the bottom of a “cocotte” or individual container, cover with the soup, and generously spread the grated Emmental cheese on top. Place them in the oven for about 5 minutes or until the cheese has nicely browned and serve.
Tips and tricks:
- The original recipe calls for meat broth, but it can be replaced by a chicken or vegetable one.
- Its possible to use other cheeses, but Emmental gives an ideal touch, since it is easy to gratin and is neither very delicate nor very predominant.
- Any type of onion will give an excellent result, as long as attention and care are paid to the caramelization process, taking care above all that it does not burn. Red onion types, especially the Italian “cipolla di Tropea” are excellent for this soup, due to their naturally sweet and pleasant flavor.