French onion soup is a hearty meal in itself, with bold flavors and rich ingredients.
When choosing a cheese to add to this wholesome soup, it’s essential to choose flavors that complement and not compete with the flavors of the soup.
So, here are some of the best cheese varieties to melt on top of the soup or add to bread or croutons.
Which Cheese Is Best for French Onion Soup?
Melted cheese adds a luscious and delicious flourish to French onion soup.
Crispy hot croutons with melted cheese or a grilled cheese sandwich can also be a wonderful addition to this dish.
However, cheese has strong flavors, and not all varieties complement the bold flavors of the soup.
So, here are some cheese varieties to consider for French onion soup.
1. Gruyere
Gruyere is a classic choice for the melted cheese on a French onion soup crouton. Its rich, nutty flavor works well with caramelized onions.
You can also use other melting cheeses, depending on how strong or mild you want the topping to be.
Swiss Gruyere AOP is a firm cheese made from raw cow’s milk and aged for at least five months. Small holes may be present inside the cheese, but they aren’t required.
Gruyere melts well, which makes it useful for fondue and for a creamy crouton topping. The finished texture depends on the cheese and how you heat it.
2. Provolone
Provolone is an excellent choice for French onion soup because of its beautiful texture and rich flavors.
Provolone is a cheese of Italian origin that is made from stretched curd. When melted, it can develop the stretchy texture that makes a cheese topping appealing.
The flavor and texture depend on the style. For example, young Provolone Valpadana dolce has a mild, lightly buttery flavor and an elastic texture, while mature piccante is firmer and more intense.
Those styles differ in how they are made as well as how long they are aged, so age alone doesn’t tell you how a Provolone will taste.
If you prefer a gentler topping, choose a mild Provolone. If you want a stronger cheese flavor alongside the onions and broth, you may prefer a sharper one.
3. Swiss Cheese
Emmental-style Swiss cheese is another option for French onion soup. This is the familiar cheese with holes, rather than a description of every cheese made in Switzerland.
It can work well as a topping for the soup or its croutons. Swiss cheese melts well, although the texture depends on the product and how it is heated.
The flavor varies with the style and age. Emmentaler AOP Classic, for example, is mild and nutty, so Swiss cheese doesn’t have to be sharp.
The holes, also called eyes, form inside the cheese as gas develops during fermentation. For the crouton topping, you can grate the cheese or use slices.
Choose a product with the flavor you prefer, or mix it with another melting cheese if you want a different balance of flavors in the topping.
4. Fontina
Fontina often has a mild, buttery flavor that works well with the beef broth and caramelized onions in French onion soup.
Hence, it’s a great addition to the soup.
This cheese also melts well, making it good for fondue and cheesy dips.
This is an added benefit of using fontina cheese for French onion soup.
When you use it as a topping for the soup, fontina can melt into a creamy coating over the crouton layer.
Fontina cheese is semi-soft and derived from cow’s milk.
It ranges from ivory to pale yellow, and its flavor varies with the style and maturity. Longer-aged Fontina can have a more pronounced flavor.
So, choose a milder fontina if you want a gentler topping, or a more mature one if you prefer a stronger cheese flavor in your soup.
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5. Mozzarella
Mozzarella is a versatile cheese of Italian origin with a mild flavor. Fresh mozzarella is soft and moist, while low-moisture mozzarella is firmer and easier to grate.
Plain mozzarella usually has a gentle, milky flavor.
Hence, it works well with most ingredients.
When it melts, mozzarella can give the topping a stretchy texture.
Hence, this cheese is widely chosen as a topping for pizzas and pasta bakes.
The same property also makes it an attractive choice for pastrami and the crouton topping of French onion soup.
Its mild, creamy flavor works well if you want a topping that leaves the beef broth and caramelized onions prominent.
It can add a delicate creaminess and make the topping more appealing.
For French onion soup, low-moisture mozzarella is a useful choice because it is firm enough to grate for the topping.
Fresh mozzarella, especially the kind packed in water, is moister and may release extra liquid as it heats. How much that affects the topping depends on the product and the amount you use.
Some fresh mozzarella is made with less moisture specifically for baking, so check the product description. Grating or refrigerating mozzarella doesn’t turn it into a low-moisture variety.
6. Monterey Jack
Monterey Jack is a delicious American cheese with mild but distinct flavors.
This cow’s-milk cheese usually has a mild, buttery flavor with a little tanginess.
It’s a useful choice if you prefer a gentle cheese flavor alongside the onions and broth.
Monterey Jack has good melting properties and a good amount of moisture.
It can make a creamy topping for soup, though the way it melts depends on the cheese and how you heat it.
You can add it to French onion soup or use it in a grilled sandwich to have with your soup.
Flavored and spicy versions of Monterey Jack cheese are also available.
You can consider using these with your French onion soup if you want to infuse more flavor and spice into your dish.
7. Parmesan
Parmesan can add a nutty flavor to the topping, especially if you’re mixing different types of cheese to make a cheesy garnish.
Even a small dusting of Parmesan can elevate the flavor of the dish.
Parmesan is a hard cow’s-milk cheese. Italian Parmigiano Reggiano has a protected designation of origin, while cheeses sold as Parmesan in markets such as the U.S. can be made elsewhere.
Parmigiano Reggiano is aged for at least 12 months. Other Parmesan-style cheeses have their own aging periods, so a one-year minimum doesn’t apply to every product.
You can grate Parmesan or add thin shavings to the topping. Aged Parmigiano Reggiano is also crumbly and can be broken into chunks.
Parmesan has a delicious nutty and fruity flavor that makes it a good addition to pasta, soups, and other traditional European dishes.
You can also use it in pasta, risotto, and other soups.
The flavors of this cheese complement the meaty richness of French onion soup, making it a good addition to the recipe.
8. Jarlsberg
Jarlsberg is a semi-soft cheese made from partly skimmed cow’s milk.
Jarlsberg Original has a mild, sweet, nutty flavor and a smooth texture. That makes it a useful option if you want a mellow cheese topping for the soup.
Its large, round holes develop during fermentation.
This cheese is good for eating on its own.
You can also serve it on cheese platters with fruits and crackers.
Jarlsberg cheese melts well, making it a good choice for sandwiches, pizza, and pasta.
You can use it alone or with other types of cheese for the crouton topping of a French onion soup.
As a melted topping, it can add a creamy finish to French onion soup.
