French Onion Soup

There’s something so cozy and comforting about a bowl of homemade French Onion Soup. The combination of caramelized onions, rich broth, and gooey melted cheese over toasted bread makes this dish truly unforgettable.

It’s a classic that feels fancy but is surprisingly simple to make and it’s perfect for chilly days, date nights at home, or when you just want something warm and satisfying.

French Onion soup has deep roots in 17th-century France, particularly in Paris, where it was created from simple, inexpensive ingredients like onions, butter, and broth.

The secret to its deep, rich flavor lies in the caramelization process. Onions are slowly cooked for nearly an hour until golden brown and sweet, creating that irresistible savory-sweet base. 

The cheesy topping we all love didn’t appear until the 19th century, when restaurants began finishing the soup under a broiler to create that bubbly, golden crust of Gruyère cheese.

Ingredients

Yellow onions – The star of the show! Yellow onions develop a deep, sweet flavor when slowly caramelized. Their natural sugars break down over low heat, giving the soup its signature golden color and rich, savory-sweet base.

Salted butter – Butter adds richness and helps the onions caramelize evenly, creating a silky, golden base full of depth.

Olive oil – Paired with butter, olive oil prevents burning during the long caramelization process and gives the soup a subtle earthiness.

Minced garlic – A small but mighty addition—garlic enhances the soup’s aroma and adds a layer of savory warmth that complements the sweetness of the onions.

Sugar – A pinch of sugar helps speed up the caramelization process, intensifying the onions’ natural sweetness and deepening their color.

Seasonings (salt, black pepper, and thyme) – A simple blend that balances and enhances the flavor. Salt brings out the onions’ sweetness, black pepper adds gentle spice, and thyme lends an earthy, aromatic touch that ties the flavors together.

Dry white wine – Adds brightness and acidity to cut through the richness. It also helps deglaze the pan, lifting up all those flavorful caramelized bits.

All-purpose flour – Lightly sprinkled over the onions, flour helps thicken the soup slightly, giving it a smooth, velvety texture.

Beef broth – The hearty base that carries all the flavor. Beef broth provides depth and richness, while mixing in chicken broth creates a lighter, balanced taste.

Worcestershire sauce – Adds a subtle kick and enhances the soup’s savory character. It deepens the flavor without overpowering the onions.

Bay leaf – Infuses the soup with a gentle herbal note during simmering, rounding out the overall flavor.

Optional splash of balsamic vinegar – Just a touch adds tangy sweetness and depth, bringing out the caramelized flavor even more.

French baguette – Toasted baguette slices act as the perfect base for melted cheese, soaking up the soup beneath while staying slightly crisp on top.

Gruyère cheese – The classic choice melts beautifully, creating that golden, stretchy topping with a nutty, slightly sweet flavor.

Parmesan cheese – Adds a salty, sharp contrast that enhances the Gruyère and gives the topping an extra layer of flavor and crispness when broiled.

How To Make French Onion Soup

1. Slice the Onions

Starting from one end of the onion use a sharp knife to make even slices from root to tip, keeping your fingers curled under as you cut. Cut into thin slices for caramelizing.

2. Make

In a large Dutch oven or soup pot, melt butter and olive oil over medium-low heat. Add sliced onions, sugar, salt, and pepper.

Cook slowly for 35–45 minutes, stirring occasionally until onions are deep golden brown and caramelized.

3. Add Garlic and Flour

Stir in minced garlic and cook for 1 minute. Sprinkle flour over the onions and stir for another 2–3 minutes to thicken the base.

4. Deglaze and Simmer

Pour in wine (if using) to deglaze the pot, scraping up any brown bits. Add broth, thyme, Worcestershire, and bay leaf.

Bring to a boil, then reduce heat and simmer for 25–30 minutes. Taste and adjust seasoning.

5. Toast the Bread

While the soup simmers, toast the baguette slices until golden.

6. Assemble and Broil

Ladle soup into oven-safe bowls. Top each with a toasted baguette slice and a generous handful of cheese.

Place under the broiler for 2–3 minutes or until the cheese is melted and bubbly. Take out and let cool.

6. Serve and Enjoy!!!

Serving Ideas

Sandwich or Salad

• Balance the rich flavors by serving French onion soup alongside a roast beef sandwich, grilled cheese, or a fresh arugula salad with vinaigrette. The lighter side helps complement the soup’s deep, savory broth.

Mini Appetizer Portions

• Serve small cups or ramekins of French onion soup as an elegant starter or party appetizer. Add mini croutons and a sprinkle of shredded cheese for easy serving. It’s a comforting, crowd-pleasing way to start a dinner or holiday gathering.

Storage and Reheating

How to Store

Refrigerator

Allow the soup to cool completely before storing. Transfer it (without the bread or cheese topping) into an airtight container and refrigerate for up to 4 days.

Freezer

If you’d like to freeze it, pour the cooled soup into freezer-safe containers or bags, leaving a little space for expansion. It will keep well for up to 3 months.

Tips for Reheating

On the Stovetop:

• Pour the soup into a pot and reheat over medium heat until hot, stirring occasionally.

In the Microwave:

• Heat individual portions in a microwave-safe bowl, covered loosely, for 1–2 minutes or until warm.

Extra Tip – Always store and reheat the soup base separately from the bread and cheese to keep the topping fresh and crisp when serving again.