Oh, that fire crackling noise, a nice book, and a large bowl of French onion soup. It’s the type of soup that gives you the feeling of being a little elegant and a lot of comfort at the same time. For me, it is the perfect recipe for a chilly night, and it is simply wonderful.

Recipe Highlights

• Deeply Flavorful: Slow-cooked onions create an incredible depth of flavor.
• Simple Ingredients: Made with humble pantry staples.
• Pure Comfort: The rich, savory broth and cheesy topping are the ultimate comfort food.

Why You’ll Love This French Onion Soup

This soup is the perfect blend of sweet and savory. It looks and tastes impressive, but it’s really just a few simple ingredients and a little bit of patience. The best part? The rich, golden broth and the blanket of melted, bubbly cheese on top. It’s a meal that feels special without being complicated.

What It Tastes Like

This soup is a beautiful dance of flavors. The onions, after a long and slow caramelization, are incredibly sweet and tender. The broth is rich, beefy, and savory. It’s not a heavy soup, but it has a deep, layered flavor that’s both comforting and elegant. The crisp bread underneath and the gooey, salty cheese on top add a final, glorious contrast.

Ingredients You’ll Need

• Yellow onions: The star of the show. You need a lot of them! The key is to slice them nice and thin and give them plenty of time to cook down. Don’t rush this step.
• Butter: This adds a rich, nutty flavor to the onions as they caramelize.
• Dry sherry or red wine: This is what makes the soup taste so complex. It deglazes the pan and adds a deep, savory note. If you don’t have sherry, a dry red wine works just as well.
• Beef broth: Use good-quality beef broth or stock. This is the base of your soup, so its flavor is very important. I like to use low-sodium so I can control the salt myself.
• Fresh thyme sprigs: Thyme adds an earthy, herby flavor that pairs beautifully with the onions. You can just toss the whole sprigs in and pull them out later.
• Salt and pepper: Seasoning is key to bringing out all the flavors.
• Baguette slices: The perfect bread for holding up in the soup. Cut them about an inch thick so they don’t turn to mush. Day-old bread works best.
• Gruyère cheese: This is the classic choice for French onion soup. It melts beautifully and has a nutty, savory flavor that complements the soup perfectly. You can also use Swiss cheese or provolone.

Step‑by‑Step Instructions

Caramelize the onions. Melt the butter in a large pot or Dutch oven over medium-low heat. Add the sliced onions and a pinch of salt. Stir well to coat them. Cook the onions slowly, stirring every 5-10 minutes, for at least 45 minutes to an hour. The key here is patience! They should be a deep, dark brown color, sticky, and very sweet. This long, slow cooking is what gives the soup its amazing flavor.

Add the liquids. Once the onions are a beautiful golden brown, pour in the sherry or wine. Scrape up all the little brown bits from the bottom of the pot—that’s all flavor! Let the liquid cook down until it’s almost gone. Then, pour in the beef broth and add the thyme sprigs.

Simmer and season. Bring the soup to a simmer and let it cook for about 20 minutes to let the flavors marry. Remove the thyme sprigs. Taste the soup and add salt and pepper as needed.

Toast the bread. While the soup simmers, place the baguette slices on a baking sheet. Broil for 2-3 minutes until they are golden brown and toasted.

Build the bowls. Ladle the hot soup into oven-safe bowls. Place a slice or two of toasted baguette on top of each bowl.

Add the cheese. You should liberally sprinkle the grated Gruyère cheese over the bread, ensuring that the whole surface is covered.

Broil and serve. Place the bowls on a baking sheet and broil on high for 2-3 minutes, or until the cheese is melted, golden brown, and bubbly. Watch it closely so it doesn’t burn! Serve immediately.

Variations, Additions, And Substitutions

You can easily make this a vegetarian soup by using a good-quality vegetable broth. Don’t have Gruyère cheese? Provolone, Swiss, or even mozzarella will melt well. For a deeper flavor, add a splash of cognac or brandy along with the sherry.

Tips for Success

• Patience is a virtue. The long caramelization of the onions is the secret to a great French onion soup.
• Don’t use a lid. Leaving the lid off helps the moisture evaporate, which is what allows the onions to brown and get that deep, sweet flavor.
• Use good broth. The broth is the foundation of the soup, so don’t skimp here.
• Broil with care. Broilers are very hot and can burn the cheese in an instant. Keep your eye on the bowls!

What to Serve With This Soup

French onion soup is a classic starter. Pair it with a simple green salad with a light vinaigrette to cut through the richness of the soup. A glass of dry white wine or a full-bodied red would also be a perfect match. You could also serve it with a ham and cheese sandwich for a fun, comforting dinner.

Storage And Reheating

The soup base stores beautifully. Let it cool completely, then transfer it to an airtight container. It will keep in the fridge for up to 5 days. You can also freeze it for up to 3 months. To serve, thaw the soup, reheat it gently, then pour it into bowls. Top with fresh toasted bread and cheese and broil as directed. Don’t store the soup with the bread and cheese on top!

Frequently Asked Questions

What kind of cheese is best for French onion soup?

Gruyère cheese is the traditional choice because it melts beautifully and has a nutty flavor. Provolone and Swiss are also great options that melt well and taste delicious.

Can I make French onion soup vegetarian?

Yes, you can. Simply use a high-quality vegetable broth instead of beef broth. The flavor will be slightly different but still delicious.

Why are my onions not caramelizing?

The most common reason is that the heat is too high. Cook the onions over a low to medium-low heat for a long period of time. It can take up to an hour.