Name: Classic French Onion Soup
Prep time: 15 min
Cook time: 1 h 10 min
Total time: 1 h 25 min
Cuisine: French
Ingredients: 4 tbsp unsalted butter; 1 tbsp vegetable oil; 3 lbs sweet onions (thinly sliced); ¾ tsp salt; ½ tsp freshly ground black pepper; ¾ tsp sugar; 1 cup dry white wine; 2 tbsp all-purpose flour; 6 cups beef broth; 1 tsp Worcestershire sauce; ½ tsp dried thyme (or fresh thyme sprigs); 2 bay leaves; 1 small baguette, sliced (½‑inch each); 1 tbsp dry sherry (optional); Gruyère cheese (enough for topping each bowl); Fresh thyme leaves or cracked black pepper for garnish

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Short description

Classic French Onion Soup features deeply caramelized onions, rich broth, and crusty, cheese-topped bread—served gratinéed for a traditional, soul-warming, savoury experience.

Why You’ll Love This Recipe

Layers of flavor from slow-cooked, golden onions
Elegant and hearty presentation with melted cheese and bread
Traditional, comforting French staple with timeless appeal
Pantry-friendly ingredients and simple technique
Ideal for cozy dinners, first courses, or uplifting comfort food

Classic French Onion Soup

Ingredients

(Tip: You’ll find the full list of ingredients and measurements in the recipe card below.)

- 4 tbsp unsalted butter
- 1 tbsp vegetable oil
- 3 lbs sweet onions (thinly sliced)
- ¾ tsp salt
- ½ tsp freshly ground black pepper
- ¾ tsp sugar
- 2 tbsp all-purpose flour
- 6 cups beef broth
- 1 tsp Worcestershire sauce
- ½ tsp dried thyme (or fresh thyme sprigs)
- 2 bay leaves
- 1 small baguette, sliced (½‑inch each)
- 1 tbsp dry sherry (optional)
- Gruyère cheese (enough for topping each bowl)
- Fresh thyme leaves or cracked black pepper for garnish

Directions

Melt butter with a little oil in a large heavy-bottomed pot over medium-high heat. Add the onions and a pinch of sugar, and stir to coat.
Lower heat to medium-low and cook the onions gently, stirring frequently, until deeply golden brown and jammy—this takes 40–60 minutes of patience.
(Optional) Add minced garlic in the final few minutes of caramelizing.
Add the broth, thyme, and bay leaf. Bring to a simmer and cook for about 20–30 minutes, allowing flavors to meld. Remove the bay leaf and adjust seasoning with salt and pepper.
Preheat your broiler or oven grill. Ladle the soup into oven-safe bowls. Top each with a slice of toasted bread and a generous layer of grated cheese.
Broil until the cheese is bubbly, golden, and slightly blistered. Watch closely to prevent burning.
Serve immediately, with the cheese melting into the soup in delicious strings.

Servings and timing

Servings: Serves 4 to 6 bowls
Prep time: 10 minutes
Cook time: 60 to 90 minutes total (including onion caramelizing and simmering)
Total time: Approximately 70 to 100 minutes, depending on depth of flavor desired

Variations

Vegetarian version: Swap beef stock for vegetable broth—still rich and flavorful
Slow-cooker shortcut: Caramelize onions partially on the stovetop, then slow-cook them for 6–7 hours with stock and aromatics for minimal hands-on effort
Cheese alternatives: Try Gouda, Fontina, or Mozzarella if Gruyère isn’t available
Extra crisp toast: Rub bread with garlic or olive oil before topping for added aroma and texture

Storage/Reheating

Refrigerate: Store soup (without bread) in an airtight container for up to 3–4 days
Freeze: The soup freezes well for up to 3 months; thaw overnight and reheat gently on the stove
Reheat: Warm on the stovetop until hot. For topping, toast fresh bread and melt cheese under the broiler just before serving

FAQs

1. Do I really need to caramelize the onions so long?

Yes—deep, slow caramelization (40–60 minutes) is key to the soup’s signature sweet, savory flavor and rich color.

2. How do I avoid soggy bread?

Broil only until the cheese is golden—this softens bread slightly, but prevents it from becoming too mushy.

3. What cheese melts best?

Gruyère is classic—its nutty, gooey texture works beautifully. Swiss, Comté, Emmental, or a mix also melt nicely.

4. Can I make this ahead of time?

Absolutely—the soup reheats well. Add bread and cheese just before serving.

5. Why add sugar to onions?

A pinch accelerates caramelization by drawing out the onions’ natural sugars and promoting browning.

6. Can I use only olive oil instead of butter?

Yes, for a dairy-free option. Butter adds richness, but oil works fine. Adjust seasoning as needed.

7. Is thyme essential?

Thyme works traditionally, but dried herb blends such as herbs de Provence are fine substitutes.

8. What side dishes pair well?

A crisp green salad, roasted root vegetables, complement the soup nicely.

9. Why broil rather than bake?

Broiling quickly melts and browns the cheese, creating that characteristic gratinéed topping without overcooking the soup.

Conclusion

Classic French Onion Soup is a timeless, comforting dish that showcases the magic of simple ingredients—caramelized onions, rich broth, and bubbling cheese on crusty bread. It’s both humble and elegant, ideal for cold evenings, cozy gatherings, or when you crave a bit of French comfort. With patience and a good pot, you’ll be rewarded with layers of flavor that make every spoonful worth it.

Jane