Classic French Onion Soup – The Ultimate Guide

What Makes French onion soup so popular?
A Short History of French Onion Soup

It's absolutely delicious! The combination of flattering wines, cheeses and caramelized onions in liquid form is heavenly. What makes it such an awesome recipe is that it's easy to make and has health benefits while tasting oh so yummy. This French onion soup recipe is a great way to show off your culinary skills to dinner guests, or to simply enjoy a winter meal. It's so easy, but sure to impress!

French Onion Soup has been around for over 300 years. While its exact origins are unknown, it is thought to have originated in France in the 18th century.

In Le Halle, which is an open-air market in Paris, French onion soups became popular during the 19th century, blurring class lines and becoming popular both with workers on their morning commute as well as nighttime revelers, partying after seeing the cabaret, who viewed the hot soup as a type of hangover recipe.

This soup gained popularity in the United States in the mid-20th century, due to its simple ingredients and easy-to-follow instructions. It has since become a staple in American cuisine, enjoyed by people of all ages and backgrounds.

What region of France is most famous for French onion soup?

There are a few different regions in France that are famous for their onion soup recipes. One of the most popular is from the Alsace region, which is located in northeastern France. This region is known for its rich and flavorful soups, and their French onion soup is no exception.

Another region that is well-known for its French onion soup is the Burgundy region. This area is located in central-eastern France and is known for its red wines and hearty dishes. The French Onion soup from this region is usually made with beef stock and often has chunks of beef or pork in it.

Finally, the city of Lyon in southeastern France is also renowned for its onion soup. Their soup is typically made with chicken broth and often has cheese melted on top of it. Although I would stress that my favorite French onion soup is made with beef stock (the classic way to make it) not chicken stock.

What onions are best for French onion soup?

For French onion soup, my number one choice is sweet onions (also known as Vidalia onions). Sweet onions have a mild, sweet flavor that really shines through in this soup. They are also much easier to caramelize than other onions, which is an important step in this recipe.

In a pinch, yellow onions will do. Yellow onions have a sharper, more pungent flavor than sweet onions.

I find that the flavor of red onions are too strong for this dish and would overpower everything else – you can try using them if you like, but sweet onions are by far the best choice!

What Ingredients are used to make French Onion Soup?

Classic homemade French onion soup is made from simple ingredients such as sweet onions (Vidalia), butter, fresh thyme, bay leaf, dry white wine, a little all purpose flour, and beef broth. The soup is them topped with toasted french bread croutons, and gruyere cheese (or other Swiss cheese).

I have seen other French onion soup recipes with contain Worcestershire sauce, but for this recipe, it's not necessary as it's not a traditional ingredient typically used. So long as your onions have caramelized for long enough, you won't need to intensify the flavor using Worchestershire.

What is French onion soup broth made of?

The broth for a good French onion soup is made with beef stock. The key ingredient, of course, is the onion. For the most appropriate flavor, try to find a sweet onion, such as a Vidalia onion.

The other key ingredients in the broth are a dry, white wine and fresh thyme. The wine adds a nice acidity to the soup and deglazes the pan, and the thyme provides a subtle herbal flavor.

What is the difference between French onion soup and regular onion soup?

French onion soup is made with sweet onions aka Vidalia onion, while regular onion soup can be made with any type of onion. French onion soup is also typically cooked longer than regular onion soup, which gives it a much deeper flavor.

Finally, French onion soup is usually served with a piece of toasted French bread croutons and cheese on top, while regular onion soup is not. Regular onion soup is usually made with a powdered commercial mix, classic French onion soup is specifically made with white wine and beef broth while regular onion soup can be made with a chicken or vegetable broth and red wine or white wine.

What is the best wine to make French onion soup with?

The best type of wine to use in French onion soup is a dry, white wine. Using a dry white wine will bring out the flavors of the sweet onions. Using a sweet wine instead would overpower and conflict with the taste of the onions. A dry wine lets the naturally sweet onion flavor shine rather than burying the onion in other flavors.

A dry white wine will also help to cut through the richness of the cheese that is typically used as a topping for French onion soup.

Some ideal white wines to use in this recipe are Chardonnay, Sauvignon Blanc, and Pinot Grigio but you can use any type of dry white wine (such as Sémillon, Muscadet etc.).

The flavor of the wine will come through in the soup so you want to make sure that you are using a wine that you enjoy drinking. A good rule of thumb is to cook with wines that you would drink on their own.

It is not recommended to use cooking wine as the flavor will stray too far from the classic French onion taste.

While it is possible to make French Onion soup with red wine, I find that pairing white wine with beef broth is the backbone of this recipe. While using red wine can make for an appetizing flavor it will not create the classic French Onion soup taste that you know and love, it will create a different type of flavor altogether.

What are the best cheeses for French onion soup?

When choosing a cheese for your French onion soup, it's important to select one that will melt well. This is why gooey cheese like Gruyere cheese and Swiss cheese are generally considered to be the best options.

Gruyère cheese is the main choice, it has a nutty flavor that pairs well with the white onions. It creates a very rich taste.

Swiss cheese is a good substitute as it provides a nice, sharp flavor that helps to cut through the sweetness of the white onions.

Emmental, a type of Swiss, is also good to use. It has a buttery somewhat fruity flavor but it is sweet, melty and also pairs super well with white onions.

Parmesan cheese has a strong, salty flavor that can also help to bring the flavors of the onions to the forefront.

Mozzarella cheese also melts quickly and easily and it is a more budget-friendly option.

Is French onion Soup healthy?

French onion soup is not only comforting and delicious but it's also packed with health benefits. Onions are a rich source of antioxidants, which help to protect cells from damage.

They're also a good source of vitamins C and B6, as well as minerals like manganese and chromium. Garlic, another ingredient in this soup, has been shown to boost immunity and protect against infection. The bone broth used as the base of this soup is full of nutrients like collagen, gelatin, and amino acids.

Is there meat in French onion soup?

Outside of the beef broth base there are no additional meats added to traditional French onion soup. While this recipe does not include meat, you're welcome to try adding some if you like!

How do you describe the flavor of French onion soup?

I would describe the flavor of French onion soup as both savory and sweet. The sweetness comes from the Vidalia onions, which are slowly caramelized in butter and sugar until they turn a deep golden brown.

And the savoriness comes from the beef broth, which is simmered with fresh thyme sprigs to infuse it with flavor.

How to make French Onion Soup from Scratch- Overview

You can find the full recipe details, including ingredient amounts and the full instructions in the recipe card at the bottom of this post, but first, here's a quick overview of how to make homemade French onion soup from scratch!

For this recipe, I made my soup in a large heavy bottom skillet with high sides, as it works best for caramelizing the onions. I find that a larger surface area works best when carmelizing onions as the moisture and steam can more easily evaporate during the cooking process. If you'd like, you can absolutely use a soup pot, but keep in mind it may take longer to caramelize your onions. You can also cook your soup in a large dutch oven. Either way, you're going to have a super yummy French onion soup!

Caramelize the onions: In a large heavy bottom skillet or pan, melt butter. Add the sliced onions, stir to combine with the butter and allow to cook at medium high heat. Do not stir yet! Allow the onions to cook for at least 5-8 minutes before you stir – this will allow your onions to begin to caramelize. Repeat this until the onions have become brown and caramelized – stirring occasionally is best as too frequent of stirring will prevent the onions from caramelizing.

The onions need to stay in contact with the surface of the pan for a while in order to brown up enough to pull the flavor out of the onions. I like to cook my onions for at least 40 minutes in order to brown up enough. You may need to adjust your temperature as the onions cook – higher or lower depending on how caramelized they're getting. You'll be ready for the next step once the onions are sticky and a rich brown color. 

Add the herbs/aromatics: Next add garlic, the bay leaf, fresh thyme, salt and pepper. Give everything a stir to combine. All purpose flour is then sprinkled into the onion mixture one tablespoon at a time, stirring in between, being careful to stir out any lumps. The mixture should get more sticky.

Deglaze the pan: Next, dry white wine is added to the pan to deglaze – basically, in this step, the wine will pick up all the tasty bits that are on the bottom of the pan and help re-incorporate it into the onion mixture. When combining with the wine, be sure to use your spoon to scrape up any bits that are sticking to the bottom of the pan.

Add the beef broth, combine and allow to simmer over medium heat for about 30 minutes. You can allow it to simmer longer if you like – it's up to you! I find the longer the soup simmers, the better the flavor, but please simmer no less than 30 minutes for the best results. 

Add the toppings: Next, top with crusty French bread croutons, sprinkle with cheese, and melt until bubbly according to one of the methods below. Sprinkle with additional fresh thyme and serve!

To make the Crusty French Bread Croutons for the soup

Take your sliced French bread and place them on a wire rack over a rimmed baking sheet. Place them in the oven to bake for 2 minutes at 250°F. When they're ready, they should be firm and dry, like large croutons. Set aside until needed for topping your soup when serving. 

3 Methods for Melting the Cheese on your Croutons when serving French Onion Soup

There are several ways to give the cheese on your croutons a beautiful golden and melty texture! Choose whichever way works best for you – all work great!

Method 1: Ladle soup into oven safe bowls, then place a prepared crouton on top, sprinkle liberally with gruyere cheese. Place each bowl onto a metal baking sheet, then place them into the oven. Turn on your broiler and watch very closely! Once the cheese is melted and bubbly, they're ready! Be careful when serving because the bowls will be very hot – allow to rest for at least 5 minutes before serving. Sprinkle with additional fresh thyme and serve.

Method 2: After your sliced French bread has toasted in the oven, sprinkle the tops with cheese and return to the oven. Turn on the broiler setting for your oven and watch closely. Once the cheese is bubbly and golden brown, they're ready. Place the croutons with cheese on top of each bowl of french onion soup, sprinkle with additional fresh thyme and serve!

Method 3: If you have a kitchen torch, try this! This is my favorite method as it gives the cheese a nice subtle char flavor. Place toasted croutons on top of each bowl of french onion soup, sprinkle with cheese, then torch the tops until the cheese is melty and bubbly with a slight char. Sprinkle with additional fresh thyme and serve!

Alternative Cooking Methods

If you are going to make French Onion soup in a slow cooker or an instant pot my biggest piece of advice is to first caramelize onions in a pan then add it to your slow cooker or your instant pot afterward. The will give you the best flavor since it is extremely hard to get proper caramelization in an instant pot or a slow cooker. Caramelization works best in a large skillet or pan.

To make French onion soup in a slow cooker, combine all of the ingredients except for the bread and cheese in the slow cooker. Cook on low for 6-8 hours or on high for 3-4 hours. When the soup is done, ladle into oven safe bowls and top with croutons. Sprinkle with gruyere cheese and pop them under the broiler until the cheese is bubbly and golden.

To make French onion soup in an instant pot, combine all of the ingredients except for the bread and cheese in the instant pot. Cook on high pressure for 10 minutes. When the soup is done, ladle into oven safe bowls and top with croutons. Sprinkle with gruyere cheese and pop them under the broiler until the cheese is bubbly and golden.

Can I make French onion soup ahead of time?

Yes, you can make French onion soup ahead of time. Right before serving, add the crouton/crusty bread and the cheese.

How can I make French onion soup taste better?

My top tip is to use a homemade beef broth, store bought is good, but homemade is more rich and flavorful with less preservatives and will go a long way to making the best French onion soup you can make.

Caramelizing the onions until they are a deep golden brown will intensify the flavor. Using white or sweet onions (instead of yellow or red onions), will provide the correct sweet flavor for what is supposed to be a sweet soup.

Adjust seasoning and increase the amount of fresh thyme sprigs to intensify the savory part of this sweet and savory dish. You can also adjust the amount of garlic, salt and pepper to your liking.

If you want a gooey cheese that feels extra cheesy, top it with Gruyere, but if you're looking to cut back on calories, use a Swiss cheese as the topping instead.

Putting together a nice garnish will also help the flavor. A simple sprinkle of chives or green onions will do, but adding bacon on top (although not traditionally used in this soup) will also go a long way towards improving flavor.

What to Serve with French Onion Soup?

Soup is such a versatile dish, it can be served as a main course or as a side. It's also perfect for those cold winter nights when you just want something warm and comforting. French onion soup is no different, and there are so many delicious ways to enjoy it.

One of the best things about French onion soup is that it can be served with just about anything. From a simple green salad to a hearty piece of French bread, here are some of the many possibilities:

Baguette – For that extra-French vibe, slice up a baguette and enjoy it alongside your soup. The baguette slices will absorb all of the delicious flavors. Soggy bread slices will create an unappetizing texture so toasted bread is the way to go. Make your bread slices extremely crisp to pair with the soup.

Cheese – Cheese goes on top of the French onion soup but it can be enjoyed on the side as well. When it comes to the cheese that tops the soup, you're pretty much stuck with melty cheeses but for a cheese that goes on the side, any cheese you like is good! So pick your favorite type of cheese and enjoy.

Cheesy toast – You can always combine the baguette and the cheese together in some melty cheese toasts! Just make sure it is crispy.

Croutons – Croutons are nice to have on the side to add a little crunch to your soup. Can be homemade croutons or store-bought.

A simple green salad is the perfect side to any soup, and French onion soup is no exception.

Leftovers – How to Store and Reheat French Onion Soup

The best way to store French onion soup is in an airtight container in the fridge. It will last for up to 3 days.

You can also freeze French Onion soup for up to 2 months. When you're ready to eat it, just reheat it on the stove or in the microwave. You can warm it up from frozen.

When you're ready to eat it, ladle into oven safe bowls and top with croutons. Sprinkle with gruyere cheese and pop them under the broiler until the cheese is bubbly and golden.