French Onion Soup

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Carefully caramelized onions are the secret to delicious Soupe à L’oignon Gratinée — better known on this side of the pond as French Onion Soup! With each bite, the cheesy bread soaks up the broth and onions. It’s almost like au jus, only much, much tastier and much quicker to prepare!

A savory broth topped with gooey Gruyere cheese and crispy French bread, this French Onion Soup is the perfect cozy recipe to warm your soul on these chilly January evenings.

The stock for the soup is a combination of beef and chicken broths and a cup of dry red wine. This, along with the slow-cooked onions, simmers into a splendid blend of flavors. Bon Appétit!

Cold winter months call for warm, steamy soups. Or, more specifically, a crock of French Onion Soup topped with toasted croutons and melty Gruyere. What makes this delicious recipe the ultimate comfort food is the perfectly caramelized onions!

So, remember to take your time with this part of the process. You must be patient to make the most flavorful sweet, caramelized onions. Be sure to stir the ingredients often, and don’t rush!

Once your onions are a deep golden color, you’re ready to continue with the recipe.

Craving more comforting soups? Try creamy and cheesy recipes like this Chicken Florentine Soup, my classic Potato Broccoli Cheese Soup, or this savory and flavorful Sausage Tortellini Soup — YUM!

Key ingredients & substitutions for French Onion Soup Recipe

• Butter | Use unsalted butter to caramelize the sliced yellow onions. Unsalted butter is best, so you can better control the saltiness of the recipe. If preferred, you may mix oil and butter to caramelize the onions.
• Onions | Traditionally, French onion soup is made with yellow onions. However, depending on your preference, you can also make the recipe with red or white onions.

• Garlic | To bring a subtle spice to the French onion soup, use chopped garlic cloves when cooking the onions. If you’re in a pinch, substitute the fresh garlic with garlic powder.
• Fresh herbs | Bay leaves and thyme springs lend fresh and herby notes to the final flavor of the soup. If necessary, you can swap the fresh herbs for dried ones.
• Salt and pepper | Add kosher salt and freshly ground black pepper to taste.

• Red wine | Use red wine to deglaze the pot when you caramelize the onions. This ingredient also brings a deeper, richer flavor to the final soup.
• Broth | Use quality chicken and beef broth as the base of the French onion soup. These are some of the most essential ingredients, so you’ll want them to be flavorful and possibly more expensive than the other ingredients in the recipe.

• Baguette | French baguette bread is traditionally the crisp toasted crouton that tops this delicious onion soup. Of course, a freshly baked loaf from your local bakery is best.
• Gruyere | I like to sprinkle my classic French onion soup with tasty gruyere cheese, freshly grated from a block. If desired, a combination of parmesan and gruyere is also common for French onion soup recipes, as well as gouda, Swiss, or mozzarella.

How to make The Best French Onion Soup

French onion soup is easier to make than you may think! In general, you caramelize the sweet onions, add the broths, and top with melty cheese and a crisp crouton.

STEP 1 | Caramelize the onions

Begin your French onion soup by first cutting the yellow onions into slices. You want the onion slices to be thin but thick enough not to burn quickly in the pan.

Also, chop the garlic cloves and prepare the fresh herbs. You will add all these ingredients to the recipe as you caramelize the onions.

Next, place a large pot over medium heat and add the butter. Once the butter is melted, add the freshly sliced onions, chopped garlic, bay leaves, thyme sprigs, and a dash of salt and pepper.

Cook for about 25 minutes or until the onions are golden, soft, and caramelized.

STEP 2 | Add the red wine

Then, carefully pour the red wine into the pot with the caramelized onions. Reduce the heat to a simmer and cook for about five more minutes.

When the wine evaporates, and the onions look almost dry, move on to the next step.

STEP 3 | Finish making the soup broth

Now, remove the bay leaves and thyme from the pot. We attained the flavor we needed from them, but they aren’t great textures for the final soup.

Next, sprinkle flour over the onions and stir to coat them thoroughly. Set the heat to medium-low and continue cooking for another ten minutes.

Then, cautiously pour the beef and chicken broth into the pot, avoiding a messy splash. Bring the ingredients to a simmer and cook for about ten more minutes.

Finally, season to taste with a bit of salt and pepper.

STEP 4 | Toast the baguette

Your soup is almost complete! Now, it’s time to toast the bread. All you need to do is cut the baguette into large croutons or slices and set them on a baking sheet.

Place the bread in the oven and lightly toast the pieces for a couple of minutes.

STEP 5 | Top with cheese, broil, and serve!

Add the finishing touches before serving this delicious soup. Ladle the French onion broth into oven-safe bowls. Next, gently place a slice of toasted bread on top and sprinkle it with grated Gruyere cheese.

Set the bowls in the oven and broil for about three to five minutes. When the tops of the French onion soups are bubbly and golden brown, they are ready to serve!

Frequently asked questions

Can you make French Onion Soup without alcohol?

The red wine in this French onion soup recipe adds a rich flavor and helps to deglaze the pot when caramelizing the sliced onions.

Test a spoonful of the broth before boiling — you’ll see that there isn’t a strong alcohol taste. Instead, the flavors of the red wine blend with the other savory notes.

However, if you prefer to make this recipe alcohol-free, you certainly can! French onion soup is still delicious without the addition of wine.

Some recipes call for Worcestershire sauce to deepen the flavor and others use extra broth to deglaze the pot.

How do you store French Onion Soup for later?

If you have leftovers of your tasty soup, store them without the crispy croutons in an airtight container in your refrigerator for up to four days. You may also freeze french onion soup (without the bread) for up to three months.

When you’re ready to serve it again, allow the soup to thaw in the fridge overnight. Then, boil it on the stovetop, freshly make more baguette croutons, and top it with extra Gruyere cheese.

How do you successfully caramelize onions?

If you’ve ever attempted to caramelize onions, you know the process can be a little tricky. After practicing it a few times, you quickly learn the dos and don’ts, and it becomes an easy task.

For those less experienced with caramelizing onions, here are some tips to help with this crucial step.

First, remember not to slice the onions too thin. Ideally, you want the slices to be about 1/8-inch thick. Second, use a large enough pot, so the onions are not overcrowded. An overcrowded pot will need to cook for much longer, which may complicate the process.

And finally, NEVER crank up the heat. No matter how impatient you get, you must keep it low and slow. When you take your time caramelizing the onions, you should have rich brown and soft onions as a result.

Serving suggestions

Make it a soup and salad combo by serving your savory French onion soup with a refreshing salad, like this Grilled Steak Salad with French Vinaigrette, a classic Wedge Salad with Crispy Fried Shallots, or my healthy Chicken Kale Caesar Salad.

Or make a heartier meal by serving your soup with a tasty sandwich, like my Flank Steak Mediterranean Sandwich or this Turkey Melt Sandwich.

Behind the recipe: Classic French Onion Soup

This classic soup originated in Paris in the 18th century but became popular in the U.S. in the 1960s thanks to the endearing TV chef Julia Child.

If you know little about this incredible woman, I highly encourage you to research her.

Julia Child’s story is truly inspirational. She grew up in a wealthy family and studied history at Smith College. Child experienced a variety of careers before finding her passion and claim to fame—cooking!

She began with a short-lived secretarial job, then volunteered with the American Red Cross to aid in the country’s preparation for war. Soon after, she found herself as the senior typist for the OSS, a precursor to today’s CIA. 

Working in India, she met her husband, Paul Child. The couple packed their bags for Paris when Paul was assigned to another job. It was here that she finally began cooking seriously and attended the famous cooking school, Le Cordon Bleu. And the rest is history!