Classic French Onion Soup Recipe
Deeply caramelized onions in rich beef broth topped with a bubbly Gruyère crouton
By Sarah Mitchell • June 14, 2026
French onion soup is one of the most rewarding dishes in all of cooking — a pot of slow-caramelized onions transformed into a deeply savory, wine-enriched broth, served under a cap of crusty bread and bubbly, golden Gruyère cheese.
The magic is in the caramelization. Four large onions are sliced and cooked low and slow for 45 minutes, stirring occasionally, until they transform from sharp and pungent to sweet, jammy, and deeply golden. A splash of dry white wine and cognac deglazes the pan, and rich beef broth builds the body.
Ladle the soup into oven-safe crocks, float a thick slice of toasted baguette on top, pile on Gruyère, and broil until the cheese is melted, bubbly, and scorched in spots. Breaking through that cheese crust with your spoon is one of life's great pleasures.
About This Recipe
"Classic French Onion Soup" is a Soups & Stews recipe that brings yellow onions, thinly sliced, unsalted butter, olive oil, sugar and dry white wine together into a flavorful, well-balanced dish. Rated Medium and ready in about 90 minutes, this recipe fits easily into a busy schedule. It serves 4 and works equally well for a weeknight dinner or a relaxed weekend meal. The French inspiration behind this dish balances classic techniques with clean, vibrant flavors.
Ingredients
- 4 large yellow onions, thinly sliced
- 3 tbsp unsalted butter
- 1 tbsp olive oil
- 1 tsp sugar
- 1/2 cup dry white wine
- 2 tbsp cognac or brandy (optional)
- 6 cups beef broth
- 2 sprigs fresh thyme
- 1 bay leaf
- 4 thick slices baguette, toasted
- 2 cups shredded Gruyère cheese
- 1 tsp salt
- 1/2 tsp black pepper
Instructions
- 1
Melt butter with olive oil in a large Dutch oven over medium heat. Add sliced onions and a pinch of sugar. Cook for 40-50 minutes, stirring every 5 minutes, until the onions are deeply golden, jammy, and caramelized. Lower heat if they start to burn.
- 2
Pour in white wine and cognac, scraping up any browned bits from the bottom of the pot. Cook until the liquid has almost evaporated, about 2 minutes.
- 3
Add beef broth, thyme, and bay leaf. Bring to a simmer and cook for 20 minutes. Season with salt and pepper. Remove thyme sprigs and bay leaf.
- 4
Preheat your broiler. Ladle soup into oven-safe crocks and place on a baking sheet.
- 5
Float a toasted baguette slice on each bowl of soup. Pile generously with Gruyère cheese, letting it drape over the edges of the crock.
- 6
Broil for 3-4 minutes until the cheese is melted, bubbly, and golden brown in spots. Let cool slightly before serving — the soup is extremely hot under the cheese.
Expert Tips
For the best result, use the freshest, highest-quality ingredients you can find. Yellow onions, thinly sliced is the heart of this dish, so choose it with care. Read the recipe through before you start and prep all ingredients in advance (mise en place) so the cooking process is smooth. Sheet pan work especially well for this preparation. Taste and adjust salt, pepper, and acid at the end to make the flavors pop.
What To Serve With This
"Classic French Onion Soup" is a versatile Soups & Stews dish that pairs beautifully with a simple side salad, buttered green beans, roasted potatoes and classic French sides. Choose at least one fresh and one hearty side to create a balanced meal.
Storage & Reheating
Classic French Onion Soup stores well in an airtight container in the refrigerator for 2–3 days. Let it cool to room temperature before refrigerating before sealing the container. Reheat gently until warmed through, adding a small splash of liquid if needed to restore the original texture.
Nutrition Facts (per serving)
Frequently Asked Questions
How long does it take to make Classic French Onion Soup?
This recipe takes about 15 minutes of prep and 75 minutes of cooking, for a total of roughly 90 minutes. It serves 4 and is rated Medium.
How do I store leftover Classic French Onion Soup?
Store leftover Classic French Onion Soup in an airtight container in the refrigerator for up to 3-4 days. Make sure to let it cool to room temperature before refrigerating. Reheat in the oven or on the stovetop for best results.
Can I make Classic French Onion Soup ahead of time?
Yes, you can prepare Classic French Onion Soup in advance. Store it in an airtight container in the refrigerator for up to 3 days. Reheat gently before serving to preserve the best texture and flavor.
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