French Onion Soup

Chase the cold away with this delicious, sweet, and savory French Onion Soup. It's loaded with perfectly caramelized onions and topped with a crusty baguette slice slathered with gooey cheese!

Each hearty bowl of this classic French Soup is full of soul-warming and oh-so-satisfying flavors and textures.

If you're a regular reader, you know, I've come late to soups. But I've always loved this soup. In fact, this recipe is inspired by a New York City chef I met during my years in the restaurant industry.

He swore up and down that adding Marsala wine made all the difference. And I think he was right. I've made it with other wines over the years, but I've just made it a habit to keep Marsala wine stocked.

What is French Onion Soup?

A classic French onion soup recipe is made of golden brown, caramelized onions and flavorful beef broth.

But what sets it apart from other onion soups is the slice of bread covered with melty cheese on top. 

With all its savory flavors and hearty layers, you can serve this soup as a light meal on its own. But for dinner, it is usually served as an appetizer. 

The Secret to Making the Best French Onion Soup

The key to making perfectly delicious French Onion Soup for me lies in these three elements of the dish.

First are, of course, perfect caramelized onions. To achieve a restaurant-worthy soup, you have to spend time drawing out the rich sweetness of this aromatic vegetable. You can’t rush through this process!

Start sautéing the onions at a low temperature. As they say - all good things come to those who wait!

Next up is the beef broth. If you want the best French onion soup, you have to look for a good quality beef broth. You can also use good beef stock for a richer flavor, but I do not recommend using Bouillon paste or cubes.

And lastly, the bread and cheese topping. A warm, crusty baguette topped with a smooth and creamy melted Gruyere is already a treat to behold! If you genuinely want to experience great French onion soup, there is no going around these must-use ingredients. 

Why This Recipe Works

FLAVOR - This soup is wonderfully flavorful! If the combination of caramelized onions and melted Swiss cheese is not enough to convince you, I don’t know what else can!

EASE - Making this soup might take time, but it is hardly laborious too. There are no complex steps or unusual ingredients involved here, just a straightforward recipe that requires a bit of patience!

Perfect for frosty nights! This is not a seasonal dish, so you can enjoy it year-round, but boy, oh boy, this homemade French onion soup recipe is just what you need to keep you warm and toasty on those cold winter nights!

MAKE AHEAD. Play it smart! Make a big batch of the onion soup and freeze them for future soup cravings! This way, you make the most of the time spent standing in front of the stovetop. 

Ingredients

ONIONS - Yellow onions are a staple in my kitchen. Their sweet and savory flavor is well-balanced, which makes them perfect for caramelization.

HERBS - Bay leaves and thyme add flavor and aroma to the broth.

BROTH - For this recipe, you'll want to use a good-quality beef broth. And, of course, you can also make your own from scratch.

LIQUEURS - adding dry sherry and marsala wine to deglaze the caramelized onions gives the broth a depth of flavor unlike no other!

BREAD - I love using a bakery baguette for this recipe, but you can also use a slice of your favorite crusty bread. Toasting the bread ahead of time makes it firmer and will prevent the bread from being too soggy once you add it to the soup.

CHEESE - What is the traditional cheese for French Onion Soup? Gruyere cheese. If you can't find Gruyere, Swiss cheese is your next best option.

SUGAR - Adding a little bit of sugar helps caramelize the onions. You can reduce the amount or skip this, depending on your preference.

Variations and Additions

CHEESE - As I said before, Gruyere cheese is your best option, and Swiss cheese comes in a close second. You can also add a little bit of Parmesan on top of the Gruyere for an extra cheesy soup.

BREAD - Aside from baguettes, you can use croutons or other types of French bread or Italian bread. This is also an excellent opportunity to use stale bread.

WINE - A good substitute for Marsala wine is red wine. The rule of thumb when cooking with wine is to use one you like drinking! A good quality, inexpensive Pinot Noir or Shiraz will work well, too.

LEEKS - When I told a friend of mine I was working on my French Onion Soup recipe, she recommended adding a few cups of leeks. I didn't do it because I was looking to create a traditional quick and easy French Onion Soup recipe. But just know it is an option if you want to play around with the recipe.

How To Make French Onion Soup

For detailed, printable recipe instructions, please check the recipe card below.

1. Slowly sauté onions in butter and olive oil, and brown sugar for 30 minutes.
2. Add the herbs, deglaze with the liqueurs, and pour in beef broth.
3. Place sliced baguettes on a baking sheet and lightly toast them in the oven. Set aside.
4. Ladle soup into oven-safe bowls, place baguette slices on top, and sprinkle with Gruyere cheese.
5. Heat under the broiler until the cheese has melted.

Recipe Success Tips

• Use a large pot or a large Dutch Oven for cooking the onions. An overcrowded pan will steam the onions instead of sautéing them. This will result in limp and soggy onions instead of dark golden, sweet ones.
• Don't rush! This recipe takes a bit of time. The goal is to get perfectly caramelized onions, and the best way to do that is over low to medium-low heat. You don't want to risk overcooking and burning the onions.
• Use a wooden spoon to scrape the bottom of the pot to dislodge the flavor-packed browned bits when deglazing the onions.
• If you hate chopping onions, invest in a vegetable chopper. I made both French Onion Soup and Mushroom Pie in one afternoon and was super grateful I had this little gadget.

What To Serve With French Onion Soup?

You might be wondering what goes with French Onion Soup. It depends a little on when you're planning to eat it.

For dinner, this soup is often served as an appetizer. If this is your first course, you can follow up with something simple like Roasted Salmon or grilled steak.

If you're enjoying French Onion Soup for lunch, you can serve it with a Grilled Cheese Sandwich or a classic Grilled Chicken Sandwich. The possibilities are endless.

What's the best kind of onion to Make This Soup?

After coming up with what I believe to be the best French Onion Soup recipe, I can tell you that my favorites are simple yellow onions.

When I recipe tested this soup, I tried multiple types of onion.

And sweet onions (think Vidalia, Walla Walla, or Maui) came in a close second. I've also tried red onions and a combination of red and sweet onions. They were both failures.

So yes, the mellow yellow onion is the winner!

What's your best tip for making this soup?

Take your time. This is not a soup you want to rush. Caramelizing the onions properly will make all the difference.

If you start at a high temperature, you risk that the onions will turn bitter instead of sweet. So, take it nice and slow, start a low heat and gently increase it midway.

It should take at least 30 minutes for the onions to be tender, sweet, and properly caramelized. And remember, this soup reheats really well. Make a big batch on the weekend and enjoy a cup each night during the week.

Do I need to buy French Onion Soup bowls?

No, you really don't. You can use oven-safe, heatproof bowls without a problem. I make French Onion Soup quite often, so I invested in an inexpensive set. I liked this set because they are 10 ounces bowls, and that's a perfect size for me.

Can I use chicken broth instead of beef broth?

Technically no. One of the characteristics of French Onion soup is that it is made with beef broth. Unlike English onion soup which can be made with beef, vegetable, or chicken broth.

That being said. Yes, you can.

I think that while it's helpful to know the origins of a recipe, you certainly have the freedom to make it your own.

I've known a restaurant chef who made a very popular French Onion soup, and his secret was using a combination of beef and chicken broth. So there you have it. It has a lighter flavor than beef broth, so you might need to season it more.

Storing Notes

MAKE-AHEAD - This easy French onion soup recipe is perfect for making ahead - without the cheesy toast, of course.

STORE AND KEEP - How long does French Onion Soup Last? The soup will last for 3-4 days in the refrigerator. Allow the soup to cool, transfer it into an airtight container, and refrigerate.

FREEZE - You can also keep it frozen for up to three months. To reheat, let the frozen soup thaw in the fridge overnight and warm it up on the stovetop. Top with fresh bread and cheese, then broil in the oven for a few minutes.

If You Like This Recipe, Try These

Last Minute PUMPKIN SOUP - made with canned pumpkin

Loaded SWEET POTATO SOUP - flavorful and filling 5-ingredient soup

CHICKEN & POTATO SOUP - get cozy with a hot steaming cup of this soup

Rustic TOMATO SOUP - made with just 4 simple ingredients

OLD-FASHiONED POTATO SOUP - hearty comfort food

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