Classic French Onion Soup

There are evenings when all you really want is a bowl of soup. Then there are the nights you crave a bowl of rich and satisfying Classic French Onion Soup. It's a classic soup because the flavours and textures go so well together. It's early origins were most likely a simple peasant meal of onions, broth, and stale bread. The classic bistro version is made with homemade beef broth and sweet caramelized onions, topped with crunchy french bread and oozing Gruyère cheese. Aged Gruyère is the key to getting the bubbling crust because it is rich, smooth, and melts easily. So what is the difference between a good French onion soup and great French onion soup? 

It's not the recipe so much as a standard of technique. Since the stock and the onions are very prominent in the recipe, the quality of both will greatly influence the outcome. The trick is starting with good beef stock. Another important element is the proper caramelization of the onions which draws out their natural sugars and sweetness. The soup itself isn't difficult to prepare, but it is time consuming. There is no short cut. Take the time to allow the onions to caramelize and the soup to reduce, the flavours will develop and become more concentrated — more intense. The results will be an indescribably good!

The most unpleasant part of the recipe is chopping the mountains of onions needed, so you may cry a little bit! Despite that little annoyance, nothing beats a lovingly prepared onion soup, especially when it is cold and rainy outside. 

Classic French Onion Soup (Soupe a l'Oignon au Fromage)


6 large yellow onions
4 tbsp unsalted butter
1 tbsp olive oil
2 tsp all-purpose flour
8 cups of beef stock
1 cup of dry white wine (Pinot Grigio)
2 tbsp cognac or dry sherry
3 bay leaves
15 peppercorns
4 sprigs of thyme
Salt and pepper
1 baguette, cut into 1/2” thick diagonal slices
1 1/2 cups of aged Gruyere or Comté cheese, shredded or sliced


For the sachet: 

Cut a piece of cheesecloth about 7” square and place bay leaves, peppercorns and thyme in the centre and tie with kitchen twine.

For the soup: 

Cut the tips off the onions and slice them in half lengthwise pole to pole. Peel off the outer layer of the skin and cut each half in half lengthwise. Slice each quarter crosswise into 1/8” slices. Make sure all the pieces separate from each other. You might even want to wear swimming goggles for this! 

Add 4 tablespoons of unsalted butter and the olive oil to a large heavy pot, and add all the onions and one tablespoon of sea salt and turn the heat up to medium. Gently sauté, stirring often until the butter is sizzling a bit then turn the heat down to low. Stir the onions every 10 minutes or so, taking care that the onions are not burning. After 1 hour, the onion liquids will start to dry up. Continue to stir the onions over low heat until they turn a deep caramelized brown, adding a little water to prevent burning as needed until the onions are very soft and brown. It will take another 3+ hours, depending on your onions, heat levels, etc. You want to coax out their sweetness without browning them too quickly. I know that sounds like a ridiculous amount of time, but do it once and you will understand why this slow process is essential. Some people cheat by adding a teaspoon or two of sugar to hasten the process but don’t! Allow the natural sugars to develop and the flavor will be indescribably good. 

Once the onions are done, add about 2 tablespoons of flour to the onions and stir for a minute or so. This small amount doesn't cloud the broth or thicken the soup, but it does add a pleasing touch of velvety viscosity and roundness of flavor. Add the beef broth, wine, cognac, the herb sachet with several sprigs of fresh thyme, 3 fresh bay leaves (or 2 dried) and 15 peppercorns and simmer for about an hour. Wine and broth balance the sweetness of the onions. Choose a very dry white wine with little or no oak flavor, such as a Pinot Grigio, to offset the sugars in the onions. Season with salt and pepper to taste. Let simmer for an hour.

Remove the herb sachet and discard it. Remove the soup from the heat and cool to room temperature and refrigerate overnight, or up to 2-3 days, in an airtight container, to allow the flavors to “marry” each other.

For the croûtes:

Arrange the baguette slices on a baking sheet in a single layer. Bake at 400° until the bread is completely dry, crisp, and lightly browned, turning once, about 10-15 minutes. Remove from oven and set aside. Leave the broiler on.

To serve:

You can either use individual oven-proof soup bowls or one large casserole dish. Bring the soup to room temperature then heat it to boiling. Ladle the soup into the bowls, topping each with one or two croûtes (do not overlap slices) and sprinkle with a generous layer of gruyere cheese. You can also slice the gruyere with a cheese plane and cover the tops of the bowls allowing the ends to hang over the rims. Allow to cook for 3-5 minutes until the cheese is melted and bubbling around the edges. Let cool afew minutes before serving. Garnish with a sprig of thyme on top if you like.


Serves 4-6



COOKS NOTE: The soup and croûtes can be made 3 days ahead. Simply cool the soup completely, uncovered, then refrigerate in a covered container. The croûtes can be stored in an airtight container at room temperature. Reheat the soup before proceeding with the recipe.