French Onion Soup is a warm bowl of comfort food made by serving caramelized onions in beef stock. The right cheese on top is what truly makes this soup irresistible. Keep reading for suggestions of the best cheese for French Onion Soup.
French Onion Soup is an ancient soup made with caramelized onions and beef broth and topped with a slice of French bread and melted cheese. It’s a popular dish in many French restaurants and my recipe makes it quick and easy to put together.
What makes this soup truly unique and delicious is the mouthwatering, melty cheese on top of the soup. A heaping spoonful of that cheese with the oniony broth is melt-in-your-mouth perfection.
You probably have an image of what that broiled cheese looks like at the top of your bowl, but if you’ve been hunting for the perfect cheese to use for the best flavor, here are a few tips to help achieve the perfect meal!
It’s tough to pinpoint the exact origin of French Onion Soup. The truth is, onions are a common staple in soups around the world and a version of this soup was probably enjoyed by even the ancient Romans.
As far as classic French onion soup, King Louis XV is usually given credit for bringing it into popularity.
One theory is that it was first made by King Louis XV in the 18th century as a late night snack after a day of hunting. Allegedly, he went to his cupboards for something to eat and all he could find was onions, butter and champagne. He threw it all together and this delicious soup was born!
Another legend credits Nicolas Appert with making the dish for the Duke of Lorraine, Stanislas Leszczynski, the father of Queen Marie (the wife of Louis XV). After just a few bites of the soup, the Duke rushed to the kitchen to learn how to make it for the rest of his family.
Though the onions brought tears to his eyes, he insisted on learning how to make the dish so he could share it with his daughter and her court. Appert actually published a recipe for the onion soup in 1831 and gave credit to the royal family.
The truth is this simple soup of onions made in beef broth has been around for much longer, possibly dating back to the 14th century. In France it was often served in the marketplace, often with bits of other vegetables added in as well. It was a popular dish but it was usually eaten by the poor.
French Onion Soup really became a standout dish around the 1860’s when the thick slice of crusty bread and gooey cheese was added on top. This decadent addition is what has made the soup so popular around the world.
In France, the soup is considered a hangover cure because the onions successfully cover up the smell of alcohol. It is often served at weddings, late at night after guests have been drinking for some time.
The Best Cheese to Use (And Why)
Over the years you may have had French onion soup in the US made with swiss, mozzarella, parmesan cheese or even provolone, but a great French onion soup is made with Gruyère cheese.
Gruyère is a type of swiss cheese. It is a semi-hard cheese that has a slightly nutty, salty flavor and a creamy texture. Just like common swiss cheese, it is slow melting. Unlike the swiss cheese you find in most stores, it has very few holes.
Gruyère is produced in southern Switzerland. It is created in a large round wheel and has a creamy brown rind on the exterior. The interior is a very pale creamy white. Most Gruyère has been aged for three to six months.
Gruyère is the perfect kind of cheese for French onion soup because it grates well, melts well, and adds a creamy flavor to the soup–without overpowering the taste of the onions.
You can usually find Gruyère in the deli of your local supermarket, alongside the specialty cheeses.
Alternatives to Gruyère
While there’s really no true replacement for the nutty flavor and richness of Gruyère you might try these cheeses:
- Comtè: This semi-firm French cheese is very similar to Gruyère and is often used in French onion soup recipes.
- Swiss: Gruyère is a type of Swiss cheese so it makes sense that it can be used as a substitute. In general, many Swiss cheeses you’ll find at the store are more processed than Gruyère and will lack the rich depth of flavor
- Provolone: Provolone is a mild cheese that makes a decent replacement
- Fontina: Fontina is another white cheese that melts well
- Mozzarella: Mozzarella cheese melts much quicker than Gruyère and may be greasier when it melts.
- Monterey Jack: Melts well but the flavor may be too overpowering
- Gouda, Jarlsberg, Raelette or Beaufort also make good substitutions
Other ingredients for a perfect French Onion Soup
- Onions: You can use any kind of onions but the most popular are sweet onions. Yellow onions and even red onions can be used.
- Wine: I like to use white wine but red wine is also popular.
- Beef broth: I also like to include worcestershire sauce and many recipes call for a dash of balsamic vinegar. Some recipes also call for chicken broth to add more depth to the savory broth.
- Baguette or croutons: I like to use a baguette that has sat out overnight and is just a tad stale. Many other recipes call for croutons! Crispy baguette slices will hold their shape and stay at the top of your soup bowl.
- Butter: Cooking your onions over medium heat in unsalted butter is what really brings out that caramelized flavor and the perfect golden-brown color. You might be tempted to use some olive oil instead, but this soup is not the same without the rich flavor of butter.
- Herbs and Spices: Thyme, garlic, black pepper
How to Keep Your Cheese From Sinking
There is a key to keeping the golden brown, bubbly, melted cheese at the top of your French onion soup and off of the bottom of the pan: Grate it on the finest setting and make sure it is sitting on a nice thick slice of bread.
If your bread is too thin or too soft it may fold into your soup under the weight of the cheese.
If your cheese is still starting to melt into your soup, your soup may also be too thin. Try using more onions next time or less broth to thicken it up.
Should you Broil the Cheese Before or After Adding to the Soup?
Most classic French onion soup recipes tell you to add the bread to the soup, then the cheese, then broil. If you don’t have soup crocks that are safe for broiling, you can instead place the cheese on top of the bread and let that broil in the oven–then add each slice to your soup.
Either way is fine and depends on how you like the texture of the bread and cheese. If you are worried about your bread sinking, it may be a good idea to melt the cheese on the bread first. If you prefer to let your bread soak up more of the rich broth, then add your bread directly to the soup and broil them together.
Other Uses for Gruyère
If you’re not used to using Gruyère, you may not know what to do with the leftovers. The good news is once you’ve loaded your soup up with a heaping pile of grated Gruyère, there are several recipes that you can use this flavorful cheese for.
Gruyère is popular in fondue or cordon bleu recipes. It is an excellent addition to homemade macaroni and cheese. It adds great creaminess and melts so beautifully. It’s also a key ingredient for Cheese Spaetzle from Germany or this Instant Pot French Onion Chicken.
The cheese is also delicious on pizza and can pair well with white or red sauce.