French Onion Soup
This classic soup features deeply sweet caramelized onions swimming in a rich, savory beef broth. Topped with a crusty baguette slice and a blanket of melted Gruyère cheese, it's the ultimate comfort in a bowl.
For 4 servings
4 steps. 80 minutes total.
- 1
Step 1
- a.Caramelize the Onions (50-60 minutes)
- b.In a large Dutch oven or heavy-bottomed pot, melt the butter and olive oil over medium heat.
- c.Add the sliced onions and 1 tsp of salt. Stir to coat. Cook for 10-15 minutes, stirring occasionally, until the onions have softened and released their liquid.
- d.Reduce the heat to medium-low. Continue to cook for 40-50 minutes, stirring every 10 minutes, until the onions are a deep, rich brown color and have a jam-like consistency. Scrape the bottom of the pot as you stir. This slow process is crucial for developing flavor.
- 2
Step 2
- a.Build the Soup Base (5 minutes)
- b.Add the minced garlic and dried thyme to the pot and cook for 1 minute until fragrant.
- c.Sprinkle the flour over the onions and stir constantly for 1-2 minutes to cook out the raw flour taste.
- d.Pour in the white wine to deglaze the pot. Use a wooden spoon to scrape up all the browned bits (fond) from the bottom. Let it simmer until the wine has almost completely evaporated.
- 3
Step 3
- a.Simmer the Soup (20-30 minutes)
- b.Gradually whisk in the beef broth. Add the bay leaf, the remaining 0.5 tsp of salt, and the black pepper.
- c.Bring the soup to a gentle boil, then reduce the heat to low. Cover partially and let it simmer for at least 20 minutes (or up to 30 for deeper flavor) to allow the flavors to meld.
- d.Remove the bay leaf. Stir in the optional brandy or cognac. Taste and adjust seasoning if necessary.
- 4
Step 4
- a.Assemble and Broil (5 minutes)
- b.Position an oven rack about 6 inches from the broiler element and preheat the broiler.
- c.Place four oven-safe bowls on a sturdy baking sheet. Ladle the hot soup evenly into the bowls.
- d.Float one slice of baguette on top of the soup in each bowl.
- e.Generously cover the baguette and some of the surrounding soup with shredded Gruyère cheese.
- f.Carefully place the baking sheet under the broiler. Broil for 2-4 minutes, watching closely, until the cheese is melted, bubbly, and golden brown in spots.
- g.Let the bowls rest for 5 minutes before serving, as they will be extremely hot.
What to keep in mind.
6 tips from the recipe — small details that make a real difference to the final dish.
- 1Patience is key. Do not rush the onion caramelization; low and slow heat is essential for developing the deep, sweet flavor.
- 2Use a high-quality beef broth, preferably homemade or low-sodium, as it is the foundation of the soup.
- 3For extra flavor complexity, use a mix of onions, such as yellow and sweet Vidalia onions.
- 4Toast the baguette slices lightly before placing them on the soup to prevent them from becoming soggy too quickly.
- 5Always place your oven-safe bowls on a baking sheet. It makes transferring them to and from the hot oven much safer and easier.
- 6Don't skip the deglazing step with wine. The browned bits on the bottom of the pot (the fond) hold a tremendous amount of flavor.
Adapt it for your goals.
Vegetarian/Vegan
For a vegetarian version, use a rich mushroom or vegetable broth instead of beef broth. Add 1 tbsp of soy sauce or 1 tsp of miso paste to the broth for extra umami depth. For a vegan version, also use vegan butter and a plant-based cheese alternative.
Cheese VariationsCheese Variations
While Gruyère is classic, you can substitute with other great melting cheeses like Comté, Emmental, Jarlsberg, or a mix of provolone and Parmesan.
Enriched FlavorEnriched Flavor
For an even richer, restaurant-quality flavor, add a splash of dry sherry, port, or Madeira along with the brandy or cognac at the end of simmering.
Gluten FreeGluten-Free
To make this gluten-free, use a gluten-free all-purpose flour blend and top with gluten-free bread or croutons.
Why this is on our healthy list.
Rich in Antioxidants
Onions are an excellent source of quercetin, a powerful flavonoid antioxidant that helps combat inflammation, reduce allergy symptoms, and protect against chronic diseases.
Supports Gut Health
The prebiotic fibers in onions, such as inulin and fructooligosaccharides, act as food for beneficial gut bacteria, promoting a healthy digestive system and improving nutrient absorption.
Source of Collagen
When made with traditional, slow-simmered beef bone broth, this soup can be a good source of collagen and gelatin, which support the health of your joints, skin, hair, and nails.
Frequently asked questions
A typical serving of this French Onion Soup contains approximately 480-580 calories, depending largely on the amount of cheese and the thickness of the baguette used.