French Onion Soup

French Onion Soup

French onion soup is a delicious French brasserie classic that’s perfect for cold winter days. It requires slowly caramelizing a lot of onions which creates a rich, deep flavor. Topped with toasted bread and melted cheese, it’s comfort in a bowl despite the mouth pain it causes.

This French onion soup is a classic brasserie style recipe that takes time but is well worth the effort. Slow cooking onions to a deep, jammy brown sweetness forms the base of flavor. Beef broth simmers with herbs and aromatics for full-bodied depth before getting combined with the caramelized onions. A touch of flour thickens the soup while wine deglazes the pot to incorporate the fond. Umami boosters like soy sauce and fish sauce heighten the savory tones without overpowering. The soup itself is incredible but takes the decadence to another level once topped with gooey Gruyère cheese melted under the broiler. Crispy, garlicky baguette pieces soak up the rich broth for the perfect textural contrast.

As intimidating as French onion soup may seem, following the right techniques makes all the difference. Properly slicing the onions, regularly stirring during the long cook, adding stock in stages, and properly seasoning each component builds incredible complexity of flavor. While it does take active time over the course of a few hours, most of it happens unattended. Much of the work is done through slow caramelization and simmering. Put on your favorite album or podcast while you methodically prep and stir. The hands-off braising and broth simmering gives flexibility for multitasking. Keep your end goal in mind while tediously slicing pounds of onions. And be sure to account for the soup to cool before consuming – no amount of blowing will prevent burning your mouth on that delicious melted cheese!

Can I use yellow or white onions instead of Spanish onions?

You can use yellow or white onions, however Spanish onions lend a sweetness that complements the rich broth. If using regular yellow or white onions, add a little sugar during caramelization to promote browning.

What type of sherry works best?

An ideal sherry to use is a fino or amontillado which lends a subtle nuttiness. Avoid using especially sweet dessert-style sherries. Stay away from dry cooking sherries as well which have added salt and preservatives.

The soup looks curdled after adding broth to the onions, is that OK?

This is a common occurrence due the starch from the flour mixing with the hot liquid. Not to worry, the soup will even back out into a smooth, creamy consistency the longer it simmers. Just give it 5-10 minutes. You can also blend a bit to smooth it out.

Can I prepare the caramelized onions in advance?

Yes! The long-cooked onions are where most of the soup’s flavor comes from anyway. You can caramelize the onions days in advance and refrigerate until ready to use. Then simply assemble with broth, sherry, and cheeses before serving. This is a great make-ahead strategy.


  • 3 pounds Spanish onions, sliced pole to pole into thin slices
  • 6 cups (48 fl oz) high-quality beef broth
  • 2 tablespoons olive oil
  • 2 tablespoons all-purpose flour
  • 1 cup dry sherry
  • 4 cloves garlic, 2 cloves minced and 2 cloves halved
  • 1⁄4 cup chopped fresh parsley
  • 3 sprigs fresh thyme
  • 4 whole cloves (optional)
  • 10 black peppercorns
  • 1 Parmesan cheese rind (optional)
  • Kosher salt and freshly ground black pepper, to taste
  • 8 ounces Gruyere cheese, shredded
  • 1 French baguette, cut into 1⁄2 inch slices
  • 2 tablespoons chopped chives


  1. Prep the onions: Cut the onions in half from root to tip. Trim and discard the roots and stem ends. Thinly slice the onions pole to pole to maximize structure. Rinse and repeat with remaining onions.
  2. Make the broth: In a medium pot, combine beef broth, 2 halved garlic cloves, parsley, thyme, cloves, peppercorns and Parmesan rind if using. Simmer for 1 hour.
  3. Caramelize the onions: Heat the olive oil in a large Dutch oven over medium heat. Add the sliced onions, distributing evenly. Cook for 45-60 minutes, stirring frequently, until deep golden brown and very soft.
  4. Make the soup base: Sprinkle the onions with flour and cook for 1-2 minutes. Pour in the sherry and scrape up any browned bits. Once evaporated, add the strained beef broth. Simmer for 5-10 minutes.
  5. Season: Season with salt, pepper, minced garlic, soy sauce and fish sauce to taste. Recipe by
  6. Toast the bread: Toast baguette slices until crispy. Drizzle with olive oil and season with salt and pepper. Rub with a halved garlic clove.
  7. Broil the soup: Divide soup between oven-safe crocks. Top with Gruyere, then bread slices then more Gruyere. Broil 3-5 minutes until browned and bubbly.
  8. Finish and serve: Garnish with chives. Let cool slightly before carefully eating.

Enjoy this French brasserie classic! The sweet, deeply caramelized onions pair perfectly with the toasted bread and melted cheese.

Print Friendly, PDF & Email

Leave a Reply

Your email address will not be published. Required fields are marked *

You cannot copy content of this page