This is the craziest French onion soup recipe anywhere. The results are amazing and your guests will be visibly impacted by the depth of flavor. This takes a simple commoners soup from 1600s France to world-class cuisine in your home kitchen. You just need a bunch of onions and an insane amount of time.
French onion has been my favorite soup for as long as I can remember. The rich broth with browned melted cheese is hard to resist. It was in Paris that I realized that this soup can be taken to a whole new level. Down a narrow ally sat a small bistro and they served a version of this soup. The broth was intensely onion with complicated flavor notes that I had never experienced before. It was there that Jen challenged me to figure out how to make it like the French do.
I’ve found the secret is less ingredients and more technique. And much more time. A typical American recipe can be made in under an hour but the recipe here will take at least four hours over two days. I had two big discoveries as I worked on this recipe. One is to cook the onions in the oven for 2 hours before starting the caramelization process. Time in a hot oven breaks down the onions and allows for more flavor development later. The second is to spend extra time caramelizing the onions multiple times and deglazing the pan in between.
This is a great recipe for a dinner party. You make the onion broth a day or two before and then just assemble the soup with the toast and cheese as your guests are arriving. The intense flavor will knock their socks off.
History of Onion SoupOnion in a meat stock is documented back to the Romans in central Europe. Onion soup as we would recognize it is first recorded as “Portege of Onion” by Francois Pierre La Varenne in 1651 (source: FoodTimeline.org). Onions were plentiful in those days and used in many recipes in Europe. It was believed that eating raw onions caused headaches so they cooked them. Typically, over an open fire.
This soup became popular in the US in the 1960s during the French Cuisine Invasion of the US and has remained a staple of restaurant menus ever since. Unfortunately, there is a common restaurant recipe of simply sautéing onions for a few minutes, adding beef broth and then topping with inexpensive Swiss cheese. Not really worth the eight bucks they charge for it.
This is not that recipe. Here we create magic in the form of time, labor and love. Have fun. Savor that moment when your loved ones spoon in their very first taste.
Makes 8-10 servings 2 hours hands on time 4+ hours total Start 1 day before serving
- 4-5 pounds of large yellow onions, medium slice
- 4 tablespoons unsalted butter
- 1 teaspoon salt
- 1/2 cup dry sherry
- 1 tablespoon unbleached flour
- 4 cups water
- 4 cups beef stock
- 4 cups chicken stock
- 4-5 sprigs of fresh thyme
- 2 bay leaves
- Toasted baguette slices
- sliced Swiss cheese
- 6 ounces shredded Le Gruyere cheese
- Preheat oven to 400F. Coat inside of a large Dutch oven with 1 tablespoon of butter.
- Cut onions into 1/8 to 1/4 inch slices across the poles (see video). The onions should completely fill the Dutch oven approximately 4 pounds. Mix 1 teaspoon salt to the onions. Add 3 tablespoons butter to the pot. Cover with lid but leave slightly ajar. Place in oven and cook for 2 hours. Stir twice during this time.
- Remove pot from oven, remove cover and place over medium-high heat. Cook stirring occasionally until the onions begin to brown about 15 minutes.
- Slice a baguette 1/3 to 1/2 inch thick. Spread on a baking sheet and place into 400F oven for 8-10 minutes. I typically do this right after I pull out the pot of onions (here at step 3). You can store the toasted baguette slices in a sealed bag until you’re ready to serve.
- Build fond and deglaze three times: Stir frequently as browning occurs for 7-10 minutes. The color should be dark brown but not burned (see video). If it appears to begin to burn turn the heat down to medium. Deglaze the pot with 1/3 cup of water scraping the bottom with wooden spoon. Repeat this step. On the third time of building the fond use 1/2 cup dry sherry wine to deglaze the pot. It will take 2-3 minutes for the wine to cook off.
- When the wine has evaporated add 1 tablespoon flour. Stir and cook for 2 minutes. Make sure there is no dry flour left in the pot. Add 4 cups beef stock, 4 cups chicken stock, 4 cups water, 2 bay leaves, 5 sprigs of fresh thyme. Turn heat to high and bring to boil.
- Turn heat to medium low and maintain a simmer. Cover the pot and cook for 30-40 minutes. Remove bay leaves and thyme stems. Let cool down for 1-2 hours, then refrigerate overnight. This allows for additional flavor development and ease of serving for a dinner party. Note: We usually have a bowl the day we make it. Hard to resist.
- The day you plan to serve the soup, slowly re-heat on medium low. Increase heat to medium just before you want to serve and bring to a simmer. Preheat broiler on high setting. Ladle soup into oven safe bowls on a baking sheet. Add 2-3 baguette slices. Place one slice of Swiss cheese on each bowl and then sprinkle a generous amount of Le Gruyere cheese on top of each bowl.
- Preheat broiler on high. Place in oven with the top of the bowls about 2-3 inches from the broiler elements for 3-5 minutes. The cheese should be bubbling and develop nice browning. Keep a close eye on the cheese and soup.
Notes from the Guy
- You can substitute grated Swiss cheese for the Le Gruyere cheese.
- Use yellow onions or Spanish onions. Do not use sweet onions as they will make the soup too sweet and syrupy.
If you make this soup please let me know how you did in the comments section below.