We all know a warming, cozy bowl of soup completely hits the spot during the cold-weather months. French onion soup, however, is in a league of its own; it’s downright decadent, luxurious, and absolutely addictive.

Table of Contents[Hide]

An Outstanding French Onion Soup
The Best Onions for French Onion Soup
How To Slice Onions For French Onion Soup
How To Caramelize Onions
The Broth For French Onion Soup
Ingredients & Notes
How To Make French Onion Soup
FAQ’s
More Delicious Soup To Try

I love to serve this crowd-pleasing soup during the holidays as a starter to a light meal, or as the main course with a few lighter sides. No matter how you serve it, you will get plenty of oooo-la-la’s when you bring this gorgeous and utterly delicious soup to the table.

An Outstanding French Onion Soup

Topped with golden crusted bread and bubbling, gooey cheese, French onion soup could not be more visually appealing. So why is it we have all had way too many bowls of very crappy French onion soup once we dig in? The answer is simple: underneath all that decadent topping, a truly fabulous French onion soup must also have a rich, beefy, and fragrant broth.

Thankfully, despite its somewhat intimidating French-ie pedigree, it is very simple and easy to make a fabulous French onion soup at home. All you need is a little time, patience, and a willingness to pay attention to the two major components of the soup: The onions and the broth.

So let’s start with the onions. You will need a very big pile of sliced onions, and you will need to caramelize them well. Caramelizing onions is simple (more on that below), but you have to dedicate some time to the process. Cooking the onions low and slow until they become sweet and golden brown is essential for creating those deep, bold flavours in the soup.

As for the broth, we all know a homemade stock will make any soup taste a million times better. That said, if you caramelize your onions properly, a bold, complex, and astonishingly delicious broth can also be achieved with a good-quality store-bought broth.

Keep scrolling for a deep dive on how to make the French onion soup of your dreams.

The Best Onions for French Onion Soup

You will find many French onion soup recipes call for a sweet onion, such as Vidalia. I find these onions too sweet, particularly once caramelized. Red onions will work, but basic yellow cooking onions, in my opinion work best. They caramelize beautifully and are easy and inexpensive to buy.

Spanish onions are one of my favourite onions to cook with but I find them a little too mild for this soup. The same goes for white onions. You can certainly use a mix of red and yellow, if you wish.

How To Slice Onions For French Onion Soup

To make French onion soup you are going to need to slice a lot of onions. Like 4 pounds of onions, which is not a fun job no matter how you slice it (ha). But if you can get past the tear-inducing task, you will be rewarded with the most comforting, utterly delicious soup that has remained a beloved classic throughout the world for years.

Ideally, for French onion soup, you want the broth to have plenty of texture from the onions, and for the onions to be visible throughout. For this reason, it is best not to slice the onions too thin, or they will disintegrate with the long cooking time. That said, you don’t want to slice them too thick either or they will take ages to caramelize.

Here is how I like to slice the onions for French onion soup:

Cut off both ends of the onion and slice it in half lengthwise (from end to end). Set it aside and proceed to do this with all the onions, cleaning up the scraps as you go along.

Next, slice each onion in half thinly, but not too thinly, from end to end. In other words, against the grain. If you need some visual guidance, this quick video is very helpful. With this method, the onion slices will be a little thicker and hold their shape better.

To help with tearing:

My best advice to prevent too much tearing while slicing this many onions, is to have all your onions peeled, and ends trimmed, before you start slicing. This is the method described above. Once you start slicing just go as quickly as possible.

Another pretty neat trick requires a gas stove. If you have a gas stove, place your cutting board as close to a burner as possible. Turn on the burner and leave it on high while you slice the onions. Works like a charm. If you have any tried and true tricks, please do share in the comment section below!

How To Caramelize Onions

Caramelized onions are made by cooking thinly sliced onions in some fat (usually butter) for a long period of time until they become deeply browned, meltingly soft, and irresistibly sweet. A proper caramelization can only happen if the natural sugars released by the onions have time to break down slowly over a gentle heat. If you rush the process, the sugar and juices being released by the onions will burn and turn bitter pretty quickly.

I have never been able to get onions to caramelize any quicker than 45 to 60 minutes. You will be setting yourself up for failure if you believe anyone that tells you otherwise. That said, I don’t always take my onions to the deepest brown possible. Especially if you are new to caramelizing onions, it is okay to stop when they have turned a lighter shade of brown than what you see in my photos. The soup will still be delicious.

To make the caramelized onions, place a large, heavy bottomed soup pot over medium-high heat. Add some butter (and/or oil) and all the sliced onions. Cover the pot and cook for 2 to 3 minutes. Uncover, toss the onions vigorously with tongs or a wooden spoon, and sprinkle with 2 teaspoons of kosher salt. Reduce heat to medium-low, cover again and cook for 10 to 12 minutes. At this point you are just letting the onions steam in the pot until they collapse in size. You shouldn’t have to worry about them but check on them once or twice, just in case.

Next, uncover the pot and increase heat to medium. Cook the onions, stirring every 3-5 minutes or so, then more frequently towards the end, until the onions have caramelized into a deep golden-brown colour. This should take anywhere from 45 to 65 minutes. It is hard to give a precise time since so many variables are at play – the pot you used, the amount of onions, the heat of your stove, etc.

In photo below, the onions are have cooked for about 20 to 25 minutes. Keep going….

Fully caramelized! These took about 60 minutes.

Once the onions are caramelized, you can proceed with the recipe.

Cook’s tips:

Add a splash of water. If at any time the onions are sticking to the pot or starting to burn a little, just add a few splashes of water and scrape up any bits stuck to the bottom of the pan.
Do not add sugar. You may think adding sugar will speed up the caramelization process. It doesn’t, and adding sugar can increase the risk of the onions burning. It also makes the soup unpleasantly candy-sweet.
Flour is not needed. Many recipes will call for adding a few tablespoons of flour to the caramelized onions in order to thicken the broth. I like a nice clear broth so I find this completely unnecessary. Furthermore, the flour will muddy the beautiful flavours of the soup.

The Broth For French Onion Soup

Not surprisingly, the broth is a very important component of French onion soup. It should be full of flavours that are rich and complex or you will not be very thrilled with the soup. If you caramelized the onions properly, you’re already half way there.

Once the onions are caramelized you add some white wine which deglazes the pan and also adds wonderful flavour. If you absolutely cannot use wine, you can use broth instead.

Beef stock is traditionally used for making the French onion soup broth. A homemade beef stock is lovely, of course, but it takes a lot of effort and time to make it. Unfortunately store-bought beef stock is usually full of less than desirable ingredients and can taste very fake. For this reason many recipes will call for using chicken stock instead. The problem is, beef stock really adds a richness to the soup that chicken stock lacks.

My solution then, is to use half of a good-quality beef broth, and half chicken broth. It’s the perfect compromise and results in a lovely broth. If you can’t find something that looks decent, opt for using a beef bouillon, such as this one.

With the stock sorted out, it’s only a matter of tossing in a few bay leaves, a few sprigs of thyme (both optional) and a few splashes of dry sherry (not optional, imho). Again, if you are avoiding alcohol, simply omit the dry sherry. I always finish the soup with a little bit of vinegar to balance the intense sweetness from the onions.

Ingredients & Notes

The ingredients used in French onion soup are very straightforward and easy to find. Here’s what you’ll need:

Onions: You will need 3 pounds of sliced yellow onions for this French onion soup recipe which means you need about 3 1/2 pounds of onions. This is usually 6 to 7 med-large onions. I buy 4 pounds in case there are some rotten ones in the bunch.
Butter: Though you can certainly caramelize the onions in oil, butter seems to work best for both flavour, and for softening the onions.
White wine: The wine will help deglaze the pan and will add a nice lightness and acidity to the broth. You can use red wine, if you prefer.
Beef and/or chicken broth: If I make my own beef stock, I will use exclusively a beef stock base. Otherwise, mixing a good-quality store-bought beef broth with chicken broth, is a safer bet. Always buy low-sodium, or even better, no-salt-added. More on what broth to use in section above.
Dry Sherry – Unless absolutely necessary, please don’t omit the dry sherry. It adds incredible flavour and a beautiful brightness to the soup.
Bay leaf and fresh thyme -French onion soup is best without the addition of strong herbs or spices. A few bay leaves and fresh thyme is all it needs for a subtle herby aroma.
White wine vinegar – I almost always add a splash of vinegar to my soups. Here, the bit of acidity balances the sweetness of the onions beautifully. You can also use sherry vinegar, white balsamic vinegar, apple cider vinegar, or red wine vinegar.
Salt and pepper – To season the soup. The sodium content of the broth you use will determine how much salt you need to add so be sure to taste before seasoning.
Bread – For topping the soup you can use slices of French baguette or any country-style bread.
Gruyère cheese – To top the bread, I am partial to the lovely flavoured, and melty Gruyere cheese. It’s subtle sweet-salty nuttiness is divine against the rich soup broth. Other similar cheeses you can use are Asiago, Swiss, Gouda, or Fontina, etc.

How To Make French Onion Soup

Caramelizing onions is a labour of love, but once that is out of the way, the soup comes together in no time.

Caramelize the onions and deglaze the pan with wine. Simmer for a few minutes until wine has reduced slightly. Add the beef stock, chicken stock, bay leaves, fresh thyme bundle (or sprigs), and season with salt and pepper.
Bring to a boil, reduce heat and simmer for 10 to 15 minutes. Remove the bay leaves and thyme bundle. Stir in dry sherry and vinegar. Taste and adjust seasoning, if necessary.
While the soup is simmering, toast the bread slices. Heat your broiler and lightly toast the bread until golden and firm. If you wish, rub the warm toasts with a raw clove of garlic (I always do). Set toasts aside.
Place the oven-safe soup bowls on a baking sheet. When soup is ready, ladle it into the bowls and top with a piece of toast (you can use two slices if they are small, or trim it to fit if too large). Sprinkle the cheese all over the top of the soup bowl. Place the baking sheet about 6-inches under the heat and broil until the cheese has completely melted, about 2-4 minutes. Watch it closely so it doesn’t burn. Serve immediately and enjoy!

Tip: If you don’t have oven-safe bowls, simply toast the bread slices, then top with the grated cheese. Place under the broiler until cheese has melted then serve the cheesy toasts alongside the soup bowls.

FAQ’s

What soup bowls are best for French onion soup?

If you like melting the cheese right in the soup, you will need oven-safe bowls. They don’t have to be anything fancy or a special designated French onion soup bowl. Any oven-safe bowl will do, even ramekins. Use smaller bowls (10 to 12-ounce) if serving as a starter, or larger bowls if serving as a main. The bowls you see in these photos are 12-ounce capacity.

Can I make a vegetarian French onion soup?

To make a vegetarian version of French onion soup, you can replace the meat-based stock with a good-quality vegetable stock.

What to serve with French onion soup?

French onion soup is a lovely starter to any meal. If serving as a starter, make the portions on the smaller side since it is a very rich and filling soup. As a main, we enjoy it alongside a mixed green salad, or with avocado toasts (the best!).

Can I make French onion soup ahead of time?

Yes! Caramelizing the onions is the only time-consuming step to making French onion soup. The good news is you can caramelize the onions up to 3 days ahead and store in the fridge until ready to use. If you want to get more out of the way, go through with preparing the broth, then store in the refrigerator for up to 4 days. When ready to finish the soup, simply top with the cheesy bread and broil.

What to do with leftover French onion soup?

French onion soup that has been topped with bread and cheese should be eaten right away. Otherwise, the bread gets too soggy and the cheese becomes unpleasantly hard. So prepare only the amount of bowls you need. Any leftover broth can be stored in the refrigerator in an airtight container for up to 4 days. When ready to use the soup, simply top with the cheesy bread and broil.

Can you freeze French onion soup?

The soup without the cheesy bread topping will freeze well. Cool completely the transfer to a freezer-safe container and store in freezer for up to 2 months. When ready to assemble, thaw the soup in the refrigerator overnight. Heat the soup in a saucepan over medium heat, without letting it boil. Top with cheesy bread and broil.

More Delicious Soup To Try

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