This classic french onion soup recipe is loaded with caramelized onions, savory beef broth, and herbs, topped with homemade croutons and delicious gooey gooey melty cheese! Serve it as a side or a meatless dinner idea paired with a fresh side salad and french dressing--Voila!
- The Best Recipe for French Onion Soup
- Ingredients in French Onion Soup
- Homemade French Onion Soup Variations
- How To Make French Onion Soup
- What To Serve With French Onion Soup
- How To Store Traditional French Onion Soup
- Classic French Onion Soup Recipe FAQs
- Classic French Onion Soup Recipe
- More Delicious Recipe To Try
The Best Recipe for French Onion Soup
Traditional Onion Soup. I love this classic traditional onion soup loaded with slowly caramelized onions in a flavorful beef broth. It is topped with a crouton and LOTS of cheese for the perfect cheesy bite every time!
Amazing Flavors! This soup is filled with layers of flavor, so you have the best, most flavorful french onion soup. Sweet caramelized onions, dark beef broth, dry white wine, garlic, thyme, homemade crunchy crouton topper with nutty gruyere cheese. Yum!
Healthy. This recipe is gluten free, low carb, and can be keto friendly. Make this healthier by making swaps such as using fat-free beef broth or use bone broth, reducing the amount of cheese used, or omitting butter for olive oil. Enjoy it on its own, or pair it with a healthy side salad to keep it balanced.
Ingredients in French Onion Soup
Here are the ingredients you will need to make french onion soup:
- Red Onions
- Sweet Yellow Onions
- Olive Oil: substitute with your preferred oil.
- Butter: unsalted butter is best so you can control the amount of sodium in your soup.
- Garlic Cloves: mince fresh garlic cloves or use store-bought minced garlic.
- Dry White Wine: you can use any brand of port, sauvignon blanc, white cooking wine, or vermouth.
- Beef Broth: use regular, low sodium, or fat-free based on preference. You could also use beef stock instead of broth.
- White Wine Vinegar
- Beef Bouillon Base: any beef base works--better than bouillon liquid soup base or granulated base.
- Fresh Thyme: fresh thyme is best, or you can use a different fresh herb such as tarragon or marjoram.
- Kosher Salt & Ground Black Pepper
- Shredded Gruyere Cheese: shredded Swiss cheese or mozzarella cheese can be used as well.
- Optional: Cornstarch thickener using a 1:1 ratio. 1 tablespoon flour mixed with 1 tablespoon water.
- French Baguette or French Bread: cut the bread into slices to create the croutons. I like the size of the baguette slices for the size of the serving dishes, but both work well!
- Olive Oil:
- Kosher Salt
For exact ingredient quantities, please see the recipe card below!
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Homemade French Onion Soup Variations
- Substitute fresh thyme with fresh tarragon or marjoram.
- Use all one onion variety if you wish, such as all sweet or all red, or use white or yellow onions if you prefer.
- Use shredded mozzarella or any other melty cheese in place of gruyere.
- Add 1 tablespoon of Worcestershire sauce for a more beefy flavor and depth.
- Add bay leaves to your soup while simmering to add even more flavor! Remember to take it out before transferring it to your individual dishes.
- Use a dry red wine in place of the white wine for a deeper flavor profile.
- Add grated parmesan cheese with your topping for a nice salty balance.
How To Make French Onion Soup
For full instructions see the recipe card below.
To Make The Croutons
1. Brush your baguette slices with oil and salt.
2. Bake until crisp
To Make The Soup
3. Cook onions in butter until caramelized and very tender.
4. Add broth, bouillon base, wine, thyme, salt and pepper. Cover and simmer.
5. Ladle the onion soup into oven-safe bowls, place crouton on top and sprinkle with cheese.
6. Place soup on a baking sheet in the oven under the broiler. Broil until the cheese is melty.
7. Remove from oven and garnish with fresh thyme and serve!
What To Serve With French Onion Soup
- Adjust salt and pepper to taste.
- Garnish with fresh herbs like thyme, parsley, or chives.
- Serve with additional slices of French baguette or French bread and butter.
- Pair with a delicious side salad with French dressing or your favorite.
Meal idea! Serve this soup with a delicious side salad. Here are a few ideas that would pair well with this soup: fresh strawberry goat cheese salad with a maple balsamic dressing is absolutely incredible--blue cheese wedge salad is super easy to put together, and this roasted beet salad with feta and citrus vinaigrette is quite delicious. SO many options!
How To Store Traditional French Onion Soup
Allow your soup to cool and then transfer to an airtight container in the fridge for up to 3 days.
I do not recommend you freeze french onion soup as the moisture from the onions will make your soup watery when you thaw and heat it up.
Classic French Onion Soup Recipe FAQs
A few things you can do to deepen the flavor of your soup is by adding levels of flavor. This can be done by browning your butter in your Dutch oven before adding your onions and then slowly caramelizing your onions so they release all of their natural sugars. You can add balsamic vinegar to your onions as they cook or add your wine option while they cook. Add a flavored beef broth, herbs, and seasonings to add flavor to each step of cooking.
I think this depends on preference per person. Some may prefer it to be thinner or more "brothy"--while others want a creamier, thicker soup. Add a cornstarch slurry at the end of cooking before transferring it to the individual serving dishes.
If you overcook and burn your onions, they will taste very bitter. So, be careful to keep your heat medium-low and be patient about caramelizing your onions to prevent burning.
Classic French Onion Soup Recipe
- 6 (14 to 17 ounce) oven-safe soup bowls
- 3 medium red onions (thinly sliced, you will need about 3 cups)
- 3 medium yellow onions (thinly sliced, you will need about 3 cups; sweet onions may be used)
- 2 tablespoons olive oil
- 4 tablespoons butter
- 2 garlic cloves (minced)
- ½ cup dry white wine (port, sauvignon blanc, white cooking wine, or vermouth also work)
- 32 ounces beef broth (bone broth is really good here)
- 1 tablespoon white wine vinegar
- 1 teaspoon beef bouillon base
- 1 tablespoon fresh thyme
- ½ teaspoon each kosher salt and ground black pepper
- 2 cups shredded gruyere cheese (shredded swiss is fine too)
- 1 tablespoon optional thickener: cornstarch
- 6 slices french bread or baguette (sliced ½" thick)
- 4 tablespoons olive oil
- kosher salt
To Make the Croutons
- Preheat oven to 425°. Brush french bread slices with oil and lightly sprinkle with salt on both sides.
- Place on a baking sheet and bake until crisp and golden brown, about 15 to 20 minutes - flipping about halfway through. Remove from oven and set aside.
To Make the Soup
- In a large dutch oven or soup pot, melt butter and olive oil over medium-low heat. Add onions and sauté, stirring occasionally until they become very soft and golden in color. (Note: Do not rush this process - you want the onions super soft and caramelized. Do not burn the onions; reduce heat as needed.)
- Add broth, bouillon base, wine, thyme, salt, and pepper. Cover and bring to a simmer over medium heat, reducing heat if needed. Simmer for 30 minutes. Season with salt and pepper to taste.
- Turn oven to broil. Place rack about 10" from the top of the oven. Dish soup into 12-ounce oven-safe bowls, leaving about ¼" to ½" space at the top. Place the crouton on top of the soup then top each crouton with ¼ cup Gruyere cheese.
- Place soup on a baking sheet then in the oven under the broiler. Broil until cheese is melted and bubbly (be careful not to burn). (Note: The cheese may melt over the side of the bowl - that's normal.)
- Remove from oven and garnish with fresh thyme.
- Don't miss all of our helpful hints, substitution ideas, cooking tips, and other delicious recipes that can be found in our post. Check it out!
- VARIATIONS: Try fresh tarragon or marjoram instead of thyme.
- TIPS: Be sure to use bowls that are oven-safe.
- SERVING SUGGESTIONS: Adjust salt and pepper to taste. Garnish with fresh herbs like thyme, parsley, or chives. Serve with additional slices of baguette or French bread and butter. Pairs well with a tossed green salad with french dressing.
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