Classic French Onion Soup
Classic French Onion Soup is a medium French recipe that serves 4. 450 calories per serving. Recipe by Preppy Kitchen on YouTube.
Prep: 17 min | Cook: 1 hr 34 min | Total: 2 hrs 6 min
Cost: $13.17 total, $3.29 per serving
Ingredients
- 1/4 cup Unsalted Butter (cut into cubes)
- 3 lb Onions (4-6 large, thinly sliced 1/8-1/4 inch)
- 3 cloves Garlic (minced)
- 2 tablespoons All-Purpose Flour (sifted)
- 1 cup Dry White Wine (Sauvignon Blanc or cooking wine)
- 5.5 cups Beef Stock (warmed)
- 2 sprigs Fresh Thyme (leaves stripped)
- 1 leaf Bay Leaf (whole)
- 0.5 teaspoon Black Pepper (freshly cracked)
- 0.5 teaspoon Salt (kosher salt, plus extra to taste)
- 3 tablespoons Brandy (for deglazing)
- 1 baguette French Baguette (sliced 1/2 inch, toasted)
- 1 cup Gruyère Cheese (grated)
Instructions
Slice the onions
Using a sharp chef's knife, slice the onions into thin half‑moon pieces about 1/8 to 1/4 inch thick.
Time: PT10M
Mince the garlic
Peel and mince the three garlic cloves finely.
Time: PT2M
Melt butter and start cooking onions
Add 1/4 cup butter to the large pot over medium heat. Once melted, add the sliced onions and 1/2 tsp salt. Stir to coat.
Time: PT6M
Temperature: Medium heat
Soften onions
Cover the pot and cook for 5‑6 minutes until onions are slightly softened and releasing moisture.
Time: PT6M
Temperature: Medium heat
Caramelize the onions
Uncover the pot and continue cooking, stirring every few minutes, for about 60 minutes until the onions turn a deep golden‑brown color.
Time: PT1H
Temperature: Medium heat
Add garlic and flour
Stir in the minced garlic and 2 tbsp flour. Cook, stirring constantly, for 1 minute to eliminate raw flour taste.
Time: PT1M
Temperature: Medium heat
Deglaze with white wine
Slowly pour in 1 cup dry white wine while scraping the browned bits from the bottom of the pot. Stir for 2 minutes.
Time: PT2M
Temperature: Medium heat
Add stock and aromatics
Add 5½ cups warm beef stock, 2 sprigs thyme, 1 bay leaf, and ½ tsp freshly cracked black pepper. Bring to a gentle simmer.
Time: PT20M
Temperature: Medium heat
Incorporate brandy
Stir in 3 tbsp brandy and let simmer for 3 minutes so the alcohol cooks off and melds with the soup.
Time: PT3M
Temperature: Medium heat
Season and finish
Taste the soup and add more salt if needed. Remove thyme sprigs and bay leaf.
Time: PT2M
Preheat broiler
Set the oven to broil on high (about 500°F) and let it preheat while the soup rests.
Time: PT5M
Temperature: 500°F
Assemble bowls
Ladle hot soup into oven‑safe bowls, top each with toasted baguette slices and sprinkle ¼ cup grated Gruyère per bowl.
Time: PT5M
Broil the cheese
Place the bowls on a baking sheet and broil for 2 minutes, or until the cheese is bubbly and golden.
Time: PT2M
Temperature: 500°F
Serve
Remove from oven, let cool briefly, and serve hot.
Time: PT1M
Nutrition Facts
- Calories
- 450
- Protein
- 12 g
- Carbohydrates
- 35 g
- Fat
- 25 g
- Fiber
- 3 g
Dietary info: Contains dairy, Contains gluten, Contains alcohol, Not vegetarian
Allergens: Dairy, Gluten, Alcohol
Ingredient Substitutions
- Instead of Unsalted Butter: Margarine
- Instead of Onions: Yellow onions
- Instead of Garlic: Garlic paste
- Instead of All-Purpose Flour: Cornstarch (1 tablespoon)
- Instead of Dry White Wine: Chicken broth with a splash of lemon juice
- Instead of Beef Stock: Vegetable stock
- Instead of Fresh Thyme: Dried thyme (1 tsp)
- Instead of Black Pepper: White pepper
- Instead of Salt: Sea salt
- Instead of Brandy: Cognac, Dry sherry
- Instead of French Baguette: Italian bread
- Instead of Gruyère Cheese: Emmental, Swiss cheese
Equipment Needed
- Large Pot (Dutch oven)
- Chef's Knife
- Cutting Board
- Wooden Spoon or Heat‑Resistant Spatula
- Measuring Cups
- Measuring Spoons
- Box Grater
- Oven‑Safe Bowls (Ramekins)
- Baking Sheet
- Tongs (optional)
- Safety Goggles (optional)
Critical Steps — Do Not Skip
- Caramelizing the onions for a full hour
- Deglazing the pot with white wine
- Simmering with beef stock to develop flavor
- Adding brandy and allowing alcohol to cook off
- Broiling the cheese until bubbly and golden
Chef Tips from the Video
- Add a pinch of sugar with the onions to accelerate caramelization.
- Use a mixture of butter and a small amount of olive oil for richer flavor and less burning.
- Choose a high‑quality Gruyère for the best melt and flavor.
- Toast the baguette slices with a light brush of butter for extra crunch.
Troubleshooting
Onions are not dark enough after caramelizing.
Continue cooking, stirring frequently, and add a splash of water if they begin to stick.
Soup is too thick.
Stir in additional warm beef stock or water until desired consistency is reached.
Soup is too salty.
Add a little unsalted broth or water and balance with a pinch of sugar.
Storage
Refrigerator: Store soup in an airtight container for up to 4 days. Reheat gently on the stove.
Freezer: Freeze in freezer‑safe containers for up to 2 months. Thaw overnight and reheat.
Room temperature: Do not store at room temperature for more than 2 hours.
Make-Ahead Tips
- The soup base can be made a day ahead; refrigerate and reheat gently before serving.
- Toast the baguette slices in advance and store in an airtight bag.
- Grate the Gruyère ahead of time and keep refrigerated.
Frequently Asked Questions
What is the cultural significance and history of French Onion Soup in French cuisine?
French Onion Soup originated in 18th‑century France as a peasant dish that used inexpensive onions and stale bread, later becoming a classic of French bistro cooking. It symbolizes comfort and resourcefulness, turning humble ingredients into a rich, flavorful soup.
What are the traditional regional variations of French Onion Soup in France?
In Parisian bistros the soup is often finished with a broiled cheese topping, while in the Lyon region a crouton of toasted baguette is used without cheese. Some Alpine versions add a splash of brandy or cognac for extra depth.
How is French Onion Soup traditionally served in French bistros?
It is traditionally ladled into oven‑safe ramekins, topped with a thick slice of toasted baguette, covered with generous grated Gruyère, and then broiled until the cheese is bubbling and golden. It is served hot with a side of mixed greens.
During which occasions is French Onion Soup commonly enjoyed in French culture?
French Onion Soup is a popular starter during colder months, at family gatherings, and in traditional holiday meals such as Christmas Eve. It is also a staple on bistro menus for a comforting starter.
How does French Onion Soup fit into the broader French cuisine tradition?
The soup showcases classic French techniques—slow caramelization, deglazing, and finishing under a broiler—highlighting the French emphasis on building flavor layer by layer from simple ingredients.
What are the authentic traditional ingredients for French Onion Soup versus acceptable substitutes?
Authentic ingredients include yellow onions, beef stock, dry white wine, brandy, butter, Gruyère cheese, and a crusty baguette. Acceptable substitutes are vegetable stock for a vegetarian version, dry sherry for brandy, and Swiss cheese instead of Gruyère.
What other French dishes pair well with French Onion Soup?
French Onion Soup pairs beautifully with a simple green salad dressed with vinaigrette, a classic Niçoise salad, or a light herb‑infused roasted chicken. A glass of dry white wine or a crisp rosé complements the flavors.
What makes French Onion Soup special or unique in French cuisine?
Its deep, sweet‑savory flavor comes from the slow caramelization of onions, which transforms their natural sugars. The combination of broth, toasted bread, and melted Gruyère creates a comforting contrast of textures.
How has French Onion Soup evolved over time in French culinary history?
Originally a humble peasant soup, it gained popularity in 19th‑century Parisian cafés, where cheese and broiling were added. Modern versions may include brandy or different cheeses, but the core technique of caramelizing onions remains unchanged.
What are the most common mistakes to avoid when making French Onion Soup?
Common mistakes include rushing the caramelization, using too high heat which burns the onions, not deglazing properly, and over‑salting the broth. Also, failing to broil the cheese long enough can result in a soggy topping.
Why does this French Onion Soup recipe use flour as a thickener instead of a roux?
A small amount of flour is added after the onions are caramelized to lightly thicken the soup without creating a heavy roux, preserving the delicate balance of broth and onion flavor while giving a velvety texture.
Can I make French Onion Soup ahead of time and how should I store it?
Yes, you can prepare the soup base up to two days ahead. Cool it quickly, store in airtight containers in the refrigerator, and reheat gently on the stove. Add fresh toasted bread and cheese just before serving and broil.
What does the YouTube channel Preppy Kitchen specialize in?
The YouTube channel Preppy Kitchen, hosted by John Kanell, specializes in approachable, classic comfort food recipes with clear step‑by‑step instructions and a focus on technique and flavor development.
How does the YouTube channel Preppy Kitchen's approach to French cooking differ from other French cooking channels?
Preppy Kitchen emphasizes practical home‑cooking tips, such as safety goggles for onion chopping and realistic timing for caramelization, whereas many French cooking channels focus on professional techniques or elaborate plating.
Last updated: August 20, 2026
