French Onion Soup
This French Onion Soup recipe transforms humble yellow onions into a deeply flavorful, restaurant-worthy bowl of comfort. Sweet, caramelized onions simmer in a rich beef broth with a splash of wine and sherry, then get topped with toasted baguette slices and a generous blanket of melted Gruyere cheese. With a little patience for the slow caramelization, this classic bistro-style soup delivers an irresistible combination of savory, sweet, and cheesy goodness in every spoonful.
Equipment
- Dutch oven or heavy bottomed soup pot Essential for even heat distribution
- Sharp chef's knife
- Wooden spoon
- Cutting board
- Oven safe soup crocks or ramekins
- Baking sheet
- Ladle
- Measuring cups and spoons
- Mandoline slicer Optional, for even onion slices
Ingredients
- 3 pounds yellow onions thinly sliced, about 1.4kg
- 4 tablespoons unsalted butter 57g
- 2 tablespoons olive oil
- 1 teaspoon granulated sugar
- 1 teaspoon salt plus more to taste
- 3 cloves garlic minced
- 2 tablespoons all purpose flour
- 1/2 cup dry white wine 120ml
- 8 cups beef broth 1.9L, high-quality recommended
- 2 tablespoons dry sherry
- 4 sprigs fresh thyme or 1 teaspoon dried thyme
- 2 bay leaves
- 1/2 teaspoon black pepper
- 1 French baguette sliced into rounds
- 8 ounces Gruyere cheese shredded, 227g
- 1/2 cup Parmigiano Reggiano grated, for topping
Instructions
- Peel the onions and slice them thinly into half rounds, about 1/4 inch thick.
- Heat butter and olive oil in a large Dutch oven over medium heat until melted. Add onions, sugar, and salt; stir to coat.
- Reduce heat to medium-low and cook for 45-55 minutes, stirring every few minutes, until deeply golden brown and jammy.
- Stir in garlic and cook for 1 minute. Pour in wine, raise heat, and scrape up browned bits. Cook 5-8 minutes until reduced.
- Sprinkle flour over onions and stir for 1 minute. Add beef broth, sherry, thyme, bay leaves, and pepper. Bring to a boil, then simmer 30 minutes.
- While soup simmers, arrange baguette slices on a baking sheet and toast at 400°F for 8-10 minutes until golden and crisp.
- Preheat broiler. Ladle hot soup into oven-safe crocks, top with toasted baguette slices, then generously cover with shredded Gruyere and Parmigiano.
- Broil for 2-4 minutes until cheese is melted, bubbly, and lightly browned. Let cool for a minute before serving.
Notes
- Do not rush the onions. Deep caramelization takes at least 45 minutes and cannot be sped up with higher heat—low and slow is key.
- Use a combination of butter and olive oil to prevent the butter from scorching during the long cooking time.
- Choose a good quality beef broth, as it makes up most of the soup's flavor base. Homemade or low-sodium store-bought work well.
- Shred your own cheese from a block for smoother melting; pre-shredded cheese often contains anti-caking agents.
- Make the soup base a day ahead. The flavor actually improves overnight in the refrigerator.
- If the onions start sticking or browning too fast, add a splash of water to loosen the pot and continue cooking.
- For a vegetarian version, swap the beef broth for a rich vegetable broth.
- Store the soup base (without bread and cheese) in an airtight container in the refrigerator for up to 4 days, or freeze for up to 3 months.
- When reheating, warm the broth gently on the stovetop, then add fresh toasted bread and cheese before broiling.
- Substitute Gruyere with Swiss, Comte, Emmental, or fontina for a similar melt and flavor.
Nutrition
Serving: 1BowlCalories: 385kcalCarbohydrates: 32gProtein: 19gFat: 19gSaturated Fat: 10gPolyunsaturated Fat: 1gMonounsaturated Fat: 6gCholesterol: 45mgSodium: 980mgPotassium: 420mgFiber: 3gSugar: 8gVitamin A: 8IUVitamin C: 10mgCalcium: 25mgIron: 10mg
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