How to Make French Onion Soup & Why It's All About the Cheese

French onion soup

French onion soup photo credit Depositphotos

J’adore French food. The classic dishes, the wine and of course the myriad cheeses. For me, a person who eats with gusto, French restaurants are my happy place, and I know if soupe à l'oignon gratinée is on the menu, I’m going to be ordering it. It’s the perfect food. Let’s dig into why. 

The list of cheesy soups is long, but there’s only one that is 100% associated with having a crown of broiled cheese on top as its defining feature, and that is what makes French onion soup the best. Originally served as a hearty breakfast and/or hangover cure in bistros around Paris’ Les Halles market in the 18th century, the filling dish is simple to make at home too. The recipe is easy, but the question is, what kind of cheese will you put on top? What makes one type of cheese the perfect cheese for French onion soup? In most recipes, experts like Julia Child and Anthony Bourdain specifically call for Swiss cheese, and Bourdain specified Gruyère AOP, but is that the right choice?

The cheese needs to complement the soup but is also a key ingredient. The soup itself should be clear, beefy, fragrant, and balanced, without any bitter notes. The aim with the cheese is to add additional richness and mouthfeel.

 
Le Gruyère AOP wedges

What Cheese Goes with French Onion Soup?

No matter what, you’re looking for a cheese that will grate finely, melt easily and not overpower the other flavors of the soup. It should have a touch of pull and not be oily. As mentioned, the go-to for most recipes is Swiss Le Gruyère AOP which adds that nutty counterpoint to the onions and a rounded earthy note, but there are other choices out there.

 
von Trapp Farmstead Savage

von Trapp Farmstead Savage

I recently was thrilled to make the soup with von Trapp Farmstead Savage, which is a very meltable Alpine style cow’s milk cheese from Vermont. Tasting the cheese before I took the plunge, I realized it has all the notes of the soup already, so adding it to the dish elevated the warm flavors.

 
Comté AOC

I’m not married to one cheese though, so I also like to use a winter Comté AOC for the gratin because as a French Alpine cheese with its designation of origin and smooth paste it’s a natural fit. Save the aged versions for snacking. While it is essentially the same as Gruyère, the caramel notes in the younger cheese complements the onions and the nuttiness brings another depth to the stock. Read why cheesemongers favor Comté.  

If you must use gouda or mozzarella (make something else instead?) they will melt quickly, but will also be a bit oily and firm up much faster than other cheeses as it cools so the soup will have to be eaten immediately. You can also always use Emmental, which works as a great addition to any other cheese, at a 20/80 ratio. Q2

No matter what, you should make some soup. It’s never out of season.

 

French Onion Soup Recipe

French onion soup

Serves 8

Note: For this recipe you’ll need heat proof bowls or ramekins that you can put under the broiler

 Ingredients 

4 Tablespoons unsalted butter

5 pounds onions, sliced thin (I like to use a mix of brown, Maui and red)

10 cups beef broth

1 bay leaf and 4 sprigs of fresh thyme, tied into a bouquet garni

8 thick rounds of French bread, toasted

½ pound finely grated Comté

Dry sherry

Instructions 

Arrange eight heatproof ramekins on a foil lined baking sheet.

In a large Dutch oven, melt the butter over medium heat. Add half the onions, cover and let cook for 3 minutes so they begin to wilt before adding the rest. Stir every few minutes for 35 – 40 minutes.

When the onions are slightly browned, add 1 cup of the broth and stir up any caramelization on the bottom of the pan. Add the remaining broth and your bouquet garni.Reduce the heat to low and let the soup simmer for 15 minutes.

Meanwhile, preheat your broiler to high.When the soup is ready, remove the bouquet garni then carefully ladle some into each of the bowls. Add a splash of sherry to each bowl (no more than a teaspoon), add a crouton and top generously with shredded cheese.

Carefully place the baking sheet into your oven and broil until the cheese is melted and browned, which will take about eight minutes. (Keep an eye on it)

Serve the soup immediately, while the cheese is still bubbling.