Classic French onion soup

This French Onion Soup brings together buttery caramelized onions, a rich savory broth, and cheesy toasted bread for a deeply satisfying meal. Inspired by Julia Child’s famous recipe, it’s comfort in a bowl and perfect for chilly evenings when you want something warm and flavorful.

I first made this recipe on a rainy weekend and was amazed how the kitchen filled with the sweet aroma of slowly caramelizing onions. Now it’s a family favorite that always brings smiles around the table.

Ingredients

• Olive oil: Two tablespoons for starting a rich base with a hint of fruitiness
• Unsalted butter: Two tablespoons to add depth and help caramelize the onions evenly
• Yellow onions: One and a half pounds peeled halved and thinly sliced chosen for their sweetness and bright flavor
• Sugar: Half a teaspoon to accelerate and deepen the caramelization process
• Salt: One teaspoon to season the onions and balance sweetness
• All purpose flour: Three tablespoons used to thicken the soup slightly and add body
• Unsalted butter: One tablespoon added to build the roux and enrich flavor
• Beef broth: Six cups ideally low sodium so you can control salt in the soup and ensure a clean meaty taste
• Dry red wine: One cup such as Pinot Noir Côtes du Rhône or Merlot adds acidity and complexity
• Bay leaves: Two to impart subtle herbal notes
• Fresh thyme: Three sprigs for earthy fragrance
• Cognac: Three tablespoons for a warming finish that elevates the soup’s flavor complexity
• French baguette: Eight slices for toasting and topping the soup crisp and perfect for soaking up broth
• Gruyere cheese: Two cups shredded needed for its rich smooth melt and nutty flavor profile
• Parmesan cheese: Half a cup grated adds a sharp salty contrast

Instructions

Caramelize Onions:

In a large heavy pot like a Dutch oven heat olive oil and two tablespoons of butter over medium heat. When the butter melts add the onions and stir to coat. Cover the pot and cook for 20 minutes stirring every few minutes until the onions become translucent.

Continue Caramelizing:

Remove the lid and sprinkle in the sugar and salt. Cook uncovered for another 40 minutes stirring occasionally. The onions are ready when they become a deep golden color and develop a natural sweetness.

Make a Roux:

Add the flour and one tablespoon butter to the pot with the onions. Stir continuously and cook for two to three minutes to cook off the raw flour taste and create a lightly thickened base.

Deglaze the Pot:

Pour in one cup of beef broth and stir while scraping the bottom of the pot to lift any browned bits. Cook for about a minute letting the liquid evaporate slightly.

Add Broth Wine and Herbs:

Add the remaining broth to the pot then pour in the red wine. Toss in the bay leaves and thyme sprigs to infuse the soup with herbal undertones.

Simmer:

Bring the pot to a boil then lower the heat and let it simmer uncovered for 30 minutes. This allows the flavors to marry and the soup to develop depth. Remove the bay leaves and thyme after simmering.

Season and Add Cognac:

Taste the soup and adjust with salt and pepper as needed. Stir in the cognac which adds a subtle warmth and complexity to the final dish.

Prepare Bread and Cheese:

Lightly drizzle baguette slices with olive oil and toast them under a broiler for 30 seconds to one minute on each side until crisp but not burnt.

Assemble and Melt Cheese:

Ladle the soup into oven safe bowls or return the soup pot to the oven. Layer about one cup of Gruyere on top of the soup then place the toasted bread slices over the cheese. Top with remaining Gruyere and grated Parmesan. Bake at 350 degrees Fahrenheit for 20 to 25 minutes until the cheese is melted and golden brown. Serve immediately.

This soup has been a centerpiece at many family gatherings creating cozy memories around the table, especially during winter holidays.

Storage Tips

Cool the soup completely before transferring to airtight containers. It keeps well refrigerated for three to four days. When freezing divide into portions and use heavy duty freezer bags or containers to avoid freezer burn. Reheat gently on the stove to keep the cheese from becoming rubbery.

Ingredient Substitutions

If you do not have cognac brandy is a good substitute or if preferred the soup works well without alcohol. For beef broth use a good quality vegetable broth for a vegetarian version but the flavor profile will be slightly different. Instead of Gruyere Emmental cheese also melts nicely though with a milder taste.

Serving Suggestions

Serve this soup with a simple green salad tossed in a light vinaigrette to balance the richness. A crisp white wine such as Sauvignon Blanc or dry Riesling pairs beautifully with the caramelized sweetness and cheese. For a heartier meal accompany with roasted root vegetables or crusty bread brushed with garlic butter.

Enjoy this warming French onion soup with crusty toasted bread and a simple salad. It’s a comforting dish that rewards slow cooking and careful caramelization.

Your Recipe Questions Answered

→ What type of onions are best for this soup?

Yellow onions are preferred for their sweetness and bright flavor, but shallots can also add a nice balance of sweetness and depth.

→ Can I substitute the cognac in the broth?

Yes, brandy can be used as an alternative or omitted entirely without losing the soup’s essence.

→ What wine pairs well with the soup's cooking process?

Dry red wines like Pinot Noir, Côtes du Rhône, or Merlot enrich the broth’s flavor while simmering.

→ How should the bread be prepared before adding it to the soup?

Lightly drizzle olive oil and toast the baguette slices under the broiler for about 30 seconds to a minute on each side before layering them atop the soup.

→ Why use Gruyere cheese in this dish?

Gruyere melts smoothly and provides a rich, creamy texture and nutty flavor that complements the soup perfectly.

→ How long can the prepared soup be stored?

Store in an airtight container in the refrigerator for 3-4 days or freeze for up to 3 months.