The Best French Onion Soup

There are a lot of French onion soup recipes out there, but this one works because every part of it is designed for deep flavor and the right texture.

• The onions are cooked low and slow until they’re deeply caramelized, which gives the broth its signature sweetness and richness.
• The broth stays savory and balanced instead of tasting flat or overly sweet.
• The bread is toasted before broiling, so it holds up better in the soup.
• The cheese topping gets bubbly and golden, giving you that classic restaurant-style finish.

This is the kind of French onion soup that feels special enough for guests but simple enough to make at home whenever you’re craving comfort food.

How To Make French Onion Soup

Making French onion soup isn’t hard, but it does reward patience. The biggest secret is giving the onions enough time to fully caramelize before you add the broth.

1. Caramelize the onions slowly. Cook the onions until they’re deeply golden brown and almost jammy, not just softened. If they still taste sharp or look pale, keep going. This is where the soup gets most of its flavor.
2. Deglaze and build the broth. Once the onions are fully caramelized, add the sherry or wine and scrape up any browned bits from the bottom of the pot. That’s concentrated flavor. Then add the stock, thyme, and bay leaves and let everything simmer until the broth tastes rich and balanced.
3. Toast the bread first. Always toast the bread before it goes on top of the soup. This helps it hold up better instead of turning soggy too quickly.
4. Broil until bubbly and browned. Once the soup is in oven-safe bowls, top it with toasted bread and cheese, then broil just until the cheese is melted, bubbling, and browned in spots.

Don’t rush these steps

• Don’t walk away from the broiler
• Don’t stop the onions too early
• Don’t skip deglazing the pan
• Don’t use untoasted bread for the topping

This onion soup recipe is so good we used it for the inspiration for our French Onion Chicken recipe, The Best French Onion Dip and my favorite Baked French Onion Pasta.

What is French Onion Soup

French onion soup is a broth-based soup made with deeply caramelized onions and usually finished with toasted bread and melted cheese under the broiler. The flavor comes from slowly cooking the onions until they’re rich, sweet, and savory, then simmering them in stock until the broth is full of depth.

It’s a simple soup made from humble ingredients, but when done well, it tastes rich, cozy, and restaurant-worthy.

Best Onions for French Onion Soup

After testing different options, I found that yellow onions give the richest and most savory flavor for French onion soup. Sweet onions can work too, that’s what I use for my caramelized onion recipe, but they make the finished soup a little sweeter. If you want the best balance, use a mix of yellow and sweet onions.

The most important thing isn’t just which onions you choose, though. It’s making sure they cook long enough to become deeply caramelized. That’s what gives the soup its signature flavor.

Tips for Cutting Onions

For French onion soup, I like the onions sliced thinly enough to soften and melt into the broth, but not so thin that they completely disappear.

If the slices are too thick, they’ll take much longer to caramelize. If they’re too thin, they can lose all texture in the soup. Aim for thin, even slices so they cook down at the same rate and still leave you with silky strands of onion in every bite.