Perfectly caramelized onions, a rich beef broth, and cheesy toast, makes this classic French onion soup a go-to when you need a little comfort food! It’s a hearty soup recipe too good to miss!
I love French onion soup.
How could you not?
There’s onions that have been cooked down so they are sweet and delicious, crusty bread on top (soaking all that beefy broth) and copious amounts of melty cheese.
This winter soup is definitely a meal in itself. With a nice glass of red wine, you’re set!
You will use quite a bit of onions in the recipe, but they quickly cook down and, besides that, this is French onion soup, isn’t it?
And, fair warning, your breath may not thank me after eating this soup, but your belly surely will! It’s worth it, though!
What Is French Onion Soup?
Essentially, French onion soup is a big bowl of comfort food, which includes caramelized onions and beef broth with a piece of melty, cheesy bread on top.
For this onion soup, you’re gonna need:
- Onions (of course, like red, white, or yellow (or a combo of those))
- Olive oil & butter
- Flour (to thicken things a little)
- Seasonings, like salt, pepper, and thyme
- Beef broth
- Worcestershire sauce
- Balsamic vinegar
It’s amazing how some humble ingredients, like onions, along with a few other things can and be transformed into something so special!
How To Make This Soup
Full details in recipe card below, but here are the basics:
- Caramelize onions (easy step-by-step instructions to caramelize onions here).
- Add minced garlic and cook.
- Deglaze with a little wine, scraping up with a wooden spoon to get those little brown bits on the bottom of the pan (hello flavour!).
- Stir in flour (this will help thicken things).
- Add salt, pepper and thyme.
- Pour in beef broth.
- Pour in Worcestershire sauce.
- Next, pour in balsamic vinegar.
- Stir and cook a little while.
- Lay French onion soup bowls onto a sheet pan and portion soup into them.
- Top soup with bread.
- Pile on shredded cheese.
- Bake until the cheese melts.
- Carefully remove from the oven.
- Garnish with thyme (if you like).
Do I Have to Use Special French Onion Soup Bowls?
Nope! Not at all.
You do, though, have to use oven-safe bowls when baking the cheesy toast!
Tip: Don’t have oven-safe bowls? Skip putting bowls in the oven. Bake the cheesy toast separately and place on the hot soup after.
What Can I Use Instead of Gruyere Cheese?
I love Gruyere here because it’s tasty, rich, and melts well.
However, if you don’t have Gruyere cheese on hand (or simply rather use another variety), try plain Swiss cheese or Fontina.
How To Thicken Soup
You can thicken French onion soup in various ways:
- Flour: Flour was used in this recipe. Sprinkle over top when onions are cooked.
- Cornstarch slurry: You’ll want equal parts cornstarch and water. Start with 1 tablespoon each of cornstarch and cold water. Mix together before stirring into soup and heating a little until thickened. You can stir this in during the last couple of minutes of cook time.
- Reducing the soup on a low simmer: Simmer until you’ve reached your desired consistency.
- Adding more caramelized onions: More onions means a denser consistency!
- Use soup to thicken: Remove about a cup of soup from the pot and blend with an immersion blender. Then, stir back into the pot.
Tips for Making This Recipe
- This soup is super simple, but does take time (especially because there are caramelized onions involved). Just have some patience and it will be well worth it!
- Like with any soup, use a good-quality broth. Homemade beef broth would be awesome (like this beef bone broth); if you don’t have that, store-bought is perfectly fine.
- If you want to bake the cheesy toast in the oven on top of the soup, don’t fill your bowls to the brim. Once you add the bread, it will displace some of the liquid.
- Use a hearty bread that can hold up to the broth. I like focaccia or ciabatta (or something similar). Of course, no matter what you put on there it will absorb some liquid (which is awesome), but you don’t want to use a basic white bread here.
- Use a sheet pan to make things easier for putting those bowls in the oven and taking them out. Plus, the sheet pan will catch any spills, meaning less cleanup.
More Caramelized Onion Recipes
If you make this French onion soup recipe, please leave a comment below!
This recipe was originally published in September 2015 but has been updated.
French Onion Soup
- 2 tablespoons butter
- 2 tablespoons olive oil
- 3 pounds yellow onions, peeled and sliced about ⅛-inch to ¼-inch thick
- 2 cloves garlic, minced
- ⅓ cup white wine, or beef broth
- 2 tablespoons all-purpose flour
- 1 teaspoon dried thyme, or 1 tablespoon fresh thyme leaves
- ¾ teaspoon salt
- ½ teaspoon freshly ground black pepper
- 6.5 cups low sodium beef broth
- 1 tablespoon Worcestershire sauce
- 1 teaspoon balsamic vinegar
- 6 slices bread, use your favourite bread
- 1 tablespoon avocado oil, optional
- 1.5 to 2 cups shredded Gruyere cheese, depending on how much cheese you want
- Chopped fresh thyme leaves, garnish to taste (optional)
- Add butter and olive oil to a large pot or Dutch oven over medium-low heat. When butter is melted, add ⅓ of the onions. Stir to coat in butter and oil and cook 5 minutes, stirring periodically.
- After 5 minutes, add another ⅓ of the onions, stir and cook 5 minutes. Continue with remaining ⅓ of onions. Note: Because we are caramelizing a lot of onions here, I like to add in batches rather than all at once.
- Cook for about 45 minutes in total, checking on every 5 minutes or so, ensuring they aren't burning and scraping brown bits on bottom of pan and incorporating into onions. Every once in a while, add a splash of hot water to loosen any excessive brown bits and encourage the onions to cook, no more than ¼ cup at a time (up to a cup in total).
- After about 45 minutes, add garlic and cook 1 to 2 minutes.
- Once you've reached your desired caramelization, deglaze onions with wine. Stir, scrapping up any more brown bits on the bottom of the pot with a wooden spoon. Cook 1 to 2 minutes. Stir in thyme, salt, and black pepper.
- Stir in flour and cook 2 to 3 minutes.
- Pour in broth, Worcestershire sauce, and balsamic vinegar. Stir. Bring to a boil, then reduce the heat (to about medium-low heat) to a simmer. Cook 15 to 20 minutes.
- Place oven-safe French onion soup bowls onto a sheet pan and portion soup into them.Note: Don't fill those bowls to the brim. Once you add the bread, it will displace some of the liquid.Note: With my bowls, I yielded 6 servings (or bowls). If your bowls are larger, the quantity you yield may vary.
- Brush each slice of bread with a little avocado oil (optional) and place on top of soup. Distribute cheese among bread slices.
- Preheat the oven to 400 degrees Fahrenheit. Place the bowls of soup (that are on the sheet pan) into the oven and cook until the cheese is melted and a little golden (this should only take a few minutes). Carefully remove and garnish (if desired) with fresh thyme. Serve and enjoy!Note: If you don't have oven-safe bowls, omit putting the bowls into the oven. Rather portion out the soup and toast the bread with cheese separately, putting on top of the soup when serving.
A note on times provided: appliances vary, any prep and/or cook times provided are estimates only.
Tried this recipe?
If you do make this recipe, thank you!! It would mean so much if you could leave a comment below. Love to know how you enjoyed it, and it helps other readers too!