A steaming bowl of French onion soup with cheesy croutons is classic comfort food. The onions become meltingly tender and sweet with cooking. It's easy to make and the ingredients are simple. If you've only had French onion soup at a restaurant, time to make it at home. Homemade is best!
I've listed substitutions for vegetarian and vegan diners as well as options for onions and broths to make it work for everyone.
French Onion Soup Ingredients
For French onion soup you need the following ingredients:
- Onions: See notes below, use yellow, brown or sweet onions for the best flavor. Onions are the highlight of this soup.
- Fat: Both butter and olive oil work for this soup. Another option is plant-based butter.
- Broth: Beef broth, chicken broth, vegetable broth and turkey broth all work great for this soup. This recipe is all about onions and broth, so get good broth or use homemade.
- Garlic: The flavor of garlic and onions is classic, not just in this soup but in many recipes. Use fresh and chop it fine.
- Herbs: You need thyme and bay leaf. Parsley is for garnish if desired. To substitute dried thyme for fresh, use ⅓ the amount of dried. That is the standard conversion.
- Bread: Use your favorite bread for the cheesy croutons. I use either gluten-free sourdough bread or this gluten-free white bread.
- Cheese: The best cheese for French onion soup is classic Gruyere but I've listed options below in the FAQ section.
Beef broth is the classic choice but you can use chicken broth, vegetable broth or even turkey broth for delicious soup. Choose low or no sodium broth so you control the sodium level. Check out bone broths in boxes and in the freezer section.
The better the broth the better the soup so use homemade if possible. I make big batches and freeze in portions. Although the rich brown color of my batch for these photos looks like beef broth it really my roasted turkey broth!
The Best Onions
Let's talk onions! Onions are flavor powerhouses in the kitchen, sweet, savory and pungent all at the same time. What are the best onions for French onion soup? Although yellow onions are traditional you have options.
- Yellow onions (aka brown onions) are your standard onions with golden-brownish papery skins and strong flavor that mellows with cooking. Spanish onions are a milder relative.
- White onions are similar to yellow onions but milder and a bit sweeter with a white papery skin.
- Sweet onions have a higher sugar content and less sulfur, which is why you cry less when cutting them. They caramelize well. They have yellow or light brown papery skin and higher water content (juicier). Varieties are seasonal, including Walla Walla, Maui, Oso Sweet, Mayan Sweet, Texas Sweets, and Vidalia.
How to Prep Onions
Cut onions in half stem to root and slice crosswise into ¼" half rounds. For a rich flavor, I use both olive oil and butter to cook the onions but you can use all butter (regular or plant-based) or all olive oil if you prefer.
Making the Soup
Cook the sliced onions over medium low heat in a heavy pot (like a Dutch Oven). When browned and soft, deglaze with white wine (optional), add thyme sprigs and a bay leaf.
After 45 minutes of cooking, the onions are so tender they almost melt in your mouth. I know it seems like a long time, but this coaxes the best flavors out of the onions. It's worth the wait.
FAQ's and Substitutions
Beef is traditional, but chicken and turkey work great too. Choose vegetable for vegetarians.
Yes, you can omit the wine and skip the deglaze step.
Try a raw hard goat milk cheddar cheese.
Use Swiss cheese, Mozzarella, Fontina, or Gouda or a flavorful cheese that melts well.
Yes, freeze without the bread and cheese. Enjoy within 3 months.
It was the French who took the humble onion (peasant food) and elevated it to star status creating this much-loved recipe.
Substitute dried thyme, use ½ teaspoon, adding it half way through cooking the onions and leave it in the soup. For a green garnish, use a little chopped fresh parsley.
Make the soup with vegetable broth and plant-based butter/olive oil. For the cheesy croutons mix my dairy-free cheesy sprinkle with plant butter, spread on bread and toast.
How to Serve
Top the soup with toasted cheesy croutons. Make them with your bread of choice. I use gluten-free sourdough but you can use baguette slices or other artisan bread.
Broil cheese topped bread until golden and bubbly then add to the soup. Sprinkle with fresh chopped parsley for garnish if desired.
More Soup Recipes
For more soup recipes, try one of these or check the soup category for more options.
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Classic French Onion Soup
- 5 ½ quart Dutch oven or heavy pot
French Onion Soup
- 3 pounds onions
- 1 tablespoon unsalted butter or all olive oil
- 1 tablespoon olive oil or all butter
- ½ teaspoon sea salt
- ¼ teaspoon ground black pepper
- ½ cup dry white wine optional
- 3 sprigs fresh thyme or ½ teaspoon dried thyme
- 1 bay leaf
- 5 cups low sodium broth beef, chicken, turkey or vegetable
- 1 teaspoon Worcestershire optional
- 4-6 slices artisan bread
- 4 ounces Gruyere cheese
- 2-3 tablespoons grated Parmesan cheese
Slice and cook onions
- Cut onions in half through the stem end, peel and slice into ¼"thick half rounds. In a large heavy pot (5 ½ quart Dutch oven), melt the butter and olive oil over medium heat. Add the onions and allow them to cook until soft and golden brown (caramelized) about 45 minutes, stirring occasionally. Watch the onions and if browning too quickly turn your heat down.
Make cheesy croutons
- When onions are almost done, make your cheesy croutons. Cut bread so pieces fit inside the bowl. Turn on the broiler. Line a baking sheet with foil. Arrange grated cheese on top of the bread and broil until golden and bubbly. Set aside and keep warm until serving time.
Finish the soup and serve
- When onions are a rich golden brown, de-glaze the pan with the wine, scraping up and tasty bits on the bottom of the pan. If not using wine, skip this step. Cook until wine is reduced by half. Add the salt, thyme and bay leaf. Turn the heat up a bit and add the broth. Simmer on low until flavors are blended and soup is hot, about 15 minutes. Finish with Worcestershire and top with the cheesy croutons. Sprinkle with fresh parsley leaves as garnish.