This classic French onion soup is rich, warm, and full of flavor. The onions are slowly caramelized, then cooked in a mix of beef stock, herbs, and a splash of wine. Topped with cheesy toasted bread, it’s perfect for a cozy meal at home.

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Ingredients Needed:

6 large red or yellow onions (about 3 pounds)
4 tablespoons extra virgin olive oil
2 tablespoons butter
1 teaspoon sugar
Kosher salt
2 cloves garlic, minced
8 cups beef stock, chicken stock, or a combination of the two
1/2 cup dry vermouth or dry white wine
2 bay leaves
1 tablespoon fresh thyme leaves, a few sprigs of fresh thyme, OR 1/2 teaspoon dried thyme
1/2 teaspoon freshly ground black pepper
2 tablespoons brandy (optional)
8 slices (1 inch thick) French bread or baguette
1 1/2 cups grated Gruyere cheese
Sprinkling grated Parmesan cheese

How To Make French Onion Soup?

Slice the onions: Peel the onions and cut them thinly from top to bottom. You should have about 10 cups when you’re done.
Start caramelizing: heat 3 tablespoons of olive oil in a large pot over medium heat. Add the sliced onions and stir to coat. Cook for 15–20 minutes, stirring often, until they soften.
Brown the onions: turn the heat to medium-high, add the butter and the last tablespoon of olive oil, and keep stirring. Cook for another 20–40 minutes until the onions turn golden brown.
Add sugar and garlic: sprinkle in the sugar and 1 teaspoon of salt, then keep cooking until the onions get deep brown and jammy, about 10–15 minutes more. Add the minced garlic and stir for 1 more minute.
Deglaze the pot: pour in the vermouth or wine and scrape up all the browned bits stuck at the bottom of the pot.
Simmer the soup: add the stock, bay leaves, and thyme. Bring everything to a light boil, then lower the heat and cover. Let it simmer for 30 minutes.
Finish with seasoning: take out the bay leaves. Taste the soup and add more salt if needed. Stir in the pepper and brandy if you’re using it.
Toast the bread: preheat your oven to about 230°C. Line a tray with foil, brush both sides of the bread with olive oil, and toast for 5–7 minutes until golden.
Add cheese and melt: flip the bread slices, sprinkle Gruyère and Parmesan on top, and bake again until the cheese is melted and bubbly.
Serve hot: ladle the soup into bowls and top each with a cheesy toast. Or, use oven-safe bowls—add soup, place the bread on top, and broil at 350°F until the cheese is golden.

Recipe Tips:

Slice onions evenly: thin, even slices help the onions cook at the same speed. This gives a better-caramelized flavor and texture.
Use a heavy-bottomed pot: it keeps the heat steady and stops the onions from burning while they cook slowly.
Don’t rush caramelizing: it takes time—at least 45 minutes. Low heat and patience give the soup its rich, deep flavor.
Deglaze properly: scrape every brown bit from the bottom of the pot when you add the wine. That’s where the flavor hides.
Add cheese toast just before serving: don’t let the toast sit too long in the soup or it’ll get soggy. Add it right before eating for the best crunch.

How To Store & Reheat Leftovers?

Refrigerate: Let the French onion soup cool first. then pour it into a sealed container and keep it in the fridge for 4 days. Keep the bread with cheese in a separate bag or box.
Freeze: Cool the soup, then freeze it in containers for up to 3 months.
Reheat: pour the soup into a pot and warm it over medium heat, stirring occasionally, until hot.

Nutrition Facts:

Calories: 420 kcal
Total Fat: 26g
Saturated Fat: 12g
Cholesterol: 50mg
Sodium: 780mg
Potassium: 430mg
Total Carbohydrate: 28g
Dietary Fiber: 3g
Sugars: 9g
Protein: 16g

Try More James Martin Recipes:

James Martin French Onion Soup

Course: SoupsCuisine: FrenchDifficulty: Easy

Servings

servings

Prep time

minutes

Cooking time

hour

minutes

Calories

420

kcal

Ingredients

6 large red or yellow onions (about 3 pounds)
4 tablespoons extra virgin olive oil
2 tablespoons butter
1 teaspoon sugar
Kosher salt
2 cloves garlic, minced
8 cups beef stock, chicken stock, or a combination of the two
1/2 cup dry vermouth or dry white wine
2 bay leaves
1 tablespoon fresh thyme leaves, a few sprigs of fresh thyme, OR 1/2 teaspoon dried thyme
1/2 teaspoon freshly ground black pepper
2 tablespoons brandy (optional)
8 slices (1 inch thick) French bread or baguette
1 1/2 cups grated Gruyere cheese
Sprinkling grated Parmesan cheese

Directions

Slice the onions: Peel the onions and cut them thinly from top to bottom. You should have about 10 cups when you’re done.
Start caramelizing: heat 3 tablespoons of olive oil in a large pot over medium heat. Add the sliced onions and stir to coat. Cook for 15–20 minutes, stirring often, until they soften.
Brown the onions: turn the heat to medium-high, add the butter and the last tablespoon of olive oil, and keep stirring. Cook for another 20–40 minutes until the onions turn golden brown.
Add sugar and garlic: sprinkle in the sugar and 1 teaspoon of salt, then keep cooking until the onions get deep brown and jammy, about 10–15 minutes more. Add the minced garlic and stir for 1 more minute.
Deglaze the pot: pour in the vermouth or wine and scrape up all the browned bits stuck at the bottom of the pot.
Simmer the soup: add the stock, bay leaves, and thyme. Bring everything to a light boil, then lower the heat and cover. Let it simmer for 30 minutes.
Finish with seasoning: take out the bay leaves. Taste the soup and add more salt if needed. Stir in the pepper and brandy if you’re using it.
Toast the bread: preheat your oven to about 230°C. Line a tray with foil, brush both sides of the bread with olive oil, and toast for 5–7 minutes until golden.
Add cheese and melt: flip the bread slices, sprinkle Gruyère and Parmesan on top, and bake again until the cheese is melted and bubbly.
Serve hot: ladle the soup into bowls and top each with a cheesy toast. Or, use oven-safe bowls—add soup, place the bread on top, and broil at 350°F until the cheese is golden.

Notes

Slice onions evenly: thin, even slices help the onions cook at the same speed. This gives a better-caramelized flavor and texture.
Use a heavy-bottomed pot: it keeps the heat steady and stops the onions from burning while they cook slowly.
Don’t rush caramelizing: it takes time—at least 45 minutes. Low heat and patience give the soup its rich, deep flavor.
Deglaze properly: scrape every brown bit from the bottom of the pot when you add the wine. That’s where the flavor hides.
Add cheese toast just before serving: don’t let the toast sit too long in the soup or it’ll get soggy. Add it right before eating for the best crunch.