French Onion Soup is essentially caramelised onion in soup form topped with cheesy bread. The French are genius!
Caramelising onions calls for patience, but it’s worth it. You’ll be rewarded with deeply golden, intensely sweet onions that forms an incredible flavour base for this French Onion Soup. For an effortless option, see how to caramelise onions in a slow cooker!
THE ICONIC FRENCH ONION SOUP!
French Onion Soup is probably one of the most epic soups in this whole wide world. And yet, the soup itself is made with very few core ingredients: butter, onions, flour and stock/broth.
The magic is in the caramelisation of the onions, cooked slowly for at least 40 minutes. And of course the crowning glory – the glorious melted cheese toast!! Because let’s face it – French Onion Soup without the cheesy toast is just onion soup. Meh!
CARAMELISED ONIONS – STOVE OR SLOW COOKER
The caramelised onions are the star of the soup (well, on par with the cheesy toast). Making caramelised onions the classic way on the stove takes upwards of 45 minutes for a giant mound like we use for French Onion Soup.
It’s not high-stress or high-energy effort. For most of the time, the onions are cooked over low heat so you just need to stir them every now and then.
It’s the sort of thing that’s good to make while pottering around the kitchen doing other things. My cast iron pot is 24 cm / 10″ wide and it was full to the brim with raw onions and took almost an hour to caramelise. If you have a wider base pot, it will be faster – probably closer to 45 minutes.
Though of course, if this all seems like too much effort for you…… introducing….
SLOW COOKER CARAMELIZED ONIONS!!!
Yes. You. Can!!!
I first learned of this from a reader then found this recipe on TheKitchn. Terrifically convenient and totally hands off, just throw the onions in, drizzle with butter or oil then leave on low for 10 hours.
This will get you 75% of the way there. The onions are browned a bit but lack the same intensity of flavour you get from caramelising on the stove.
So you do still need to cook the onions on the stove for 10 – 15 minutes to achieve the same true flavour. And while one may wonder what’s the point, there’s a big difference between cooking down onions for almost an hour on the stove vs 10 minutes.
Plus, no having to man-handle a gigantic mound of onions in a pot that’s too small (me, me!).
THE REST IS EASY!
Caramelised onions aside, the rest of the soup is effortless. Get all the tasty brown stuff off the bottom of the pot by deglazing it with a touch of wine. A touch of flour to thicken the soup every so slightly, a LOT of broth, and an optional sprig of thyme and bay leaves.
GOOD BEEF BROTH IS A MUST!
If you use store bought, which I often do, use a good quality beef broth/stock. I personally do not recommend any of the mainstream brands sold in Australian supermarkets. I use Maggie Beer and Moredough from Harris Farms (I stock up when it’s on sale!), or private labels from butchers.
If you can’t get good quality beef broth, use chicken or vegetable instead. I find that the quality of those by mainstream brands is much better than the beef stock. The beef is fine to use in things like gravy and stews, but not when it’s a key ingredient like in this recipe.
DON’T HAVE OVEN-PROOF SOUP BOWLS?
Neither do I! Can’t justify the storage for ONE soup that calls for it. Sure, it looks thoroughly dramatic to be served a piping hot bowl from the oven with the entire surface covered in bubbling cheese (and a piece of bread under there somewhere).
But actually, I prefer making grilled cheese separately and popping them in the bowl because the bread isn’t as soggy from absorbing the soup by the time it gets to the table.
And lastly, a little tip – try the grilled cheese with your very own homemade Artisan bread. It is mind blowingly easy and has been wildly popular with readers since the day I shared it! – Nagi x
FRENCH ONION SOUP RECIPE
WATCH HOW TO MAKE IT
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French Onion Soup
Ingredients
- 100 g / 3.5oz unsalted butter
- 1.25 kg / 2.5 lb brown / yellow onions , peeled, halved, thinly sliced top to bottom (Note 1)
- 3/4 cup (185ml) dry white wine , optional (Note 2)
- 2 tbsp flour , plain / all purpose
- 1.5 litres / 6 cups / 1.5 quarts good quality beef broth./stock OR chicken , low sodium/salt reduced (Note 3)
- 2 dried bay leaves (or 3 fresh) (optional)
- 3 sprigs fresh thyme (optional)
- Salt and pepper
Cheesy Toast
- 6 - 8 slices French baguette or other softish bread (Note 4)
- 100 g / 3.5 oz gruyere or mozzarella cheese, or other melting cheese of choice
- Fresh parsley or thyme leaves , for garnish (optional)
Instructions
Caramelise Onions (See Notes for SLOW COOKER option)
- Melt butter in a heavy based casserole pot over medium heat. When it starts to foam, add onions and stir to coat in butter.
- 30 min on medium low: Turn heat down to medium low. Cook for 30 minutes stirring every few minutes, until the onions have softened and are semi transparent.
- Salt, 20 min on medium high: Turn heat up to medium or medium high. Add salt, and cook for a further 20 - 30 minutes, stirring more regularly, until onions are deep golden and sweet.
Make Soup:
- Deglaze: Add wine, then simmer rapidly for 2 minutes until mostly evaporated, stirring to scrape the bottom of the pot.
- Flour: Sprinkle flour over the onion and cook for 1 minute.
- Add broth & herbs: Add broth, thyme and bay leaves.
- Simmer: Cover, lower heat so it's simmering gently then simmer for 30 minutes.
- Serve: Season to taste with salt and pepper. Ladle into bowls. Top with 1 or 2 slices of cheesy toast.
Cheese Toast:
- Preheat grill / broiler to high.Toast each side of bread until light golden.
- Top bread with cheese, then grill until melted and some brown spots appear.
Recipe Notes:
Nutrition Information:
COMPLETE YOUR FRENCH MENU!
-
Pan Fried Fish with Brown Butter Lemon Sauce (Totally French! Poisson meunière)
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Garden salad with French Vinaigrette
-
Chocolate Mousse (classic French)
LIFE OF DOZER
I KNEW I’d find a use for those onion goggles one day! 😂 (I don’t need them, I wear contacts so I’m onion-proof. Gimme all the onions to chop!)
French Onion Soup recipe originally published in September 2016 as part of a Chasseur cast iron cookware giveaway. Since this time, the recipe has evolved (adding more flavourings – wine, thyme and bay leaves) so new photos, words and recipe video added!
Hi Nagi! Congrats on your well-deserved success! I asked for your book last Xmas & have it.
How to do the onion soup with the bone broth?
Ta!
I love French onion soup and always have it in restaurants when I see it on the menu. This is hands down the best one I have ever tasted. Thanks Nagi for this fantastic recipe!
Loved, loved, loved this soup. Simple to make and will be on my list in future. Keep up the great recipes Nagi, they are my go to.
Hello! Can I make this the day before the dinner party? Or is it best made and consumed in the same day? Thanks!
P.S. I’m creating a French degustation meal using your recipes to celebrate my 40th in a few months time! Love your work!
I’ve made this a few times and substituted various parts for what I had on hand. Tonight I made sure I had not only the ingredients required but the best quality ingredients I could get my hands on. It was sooooo worth the time and energy – so freaking good Nagi
So delicious and easy to make. Husband loved it!!
Would one be able to use dry sherry in place of the wine?
Absolutely delicious!!
Super easy to make.
I cooked the onions like the recipe said & they were amazing.
I browned off some gravy beef ‘ dumped it altogether in the slow cooker. It turned out absolutely amazing. Very hearty with the beef added. Husband is very fussy, he likes good quality food & dishes, & even he just kept saying, ‘wow’!
I just used tasty cheddar cheese’ it was great.
It freezes really well too. Def making it regularly.
This recipe was excellent but next time I’m definitely adding another half pound of onions, felt like it was lacking in that area in the end. I used homemade beef bone broth & also gave it a hit of fish sauce & cider vinegar, easily the best French Onion soup I’ve ever had.
I really needed Dozer’s googles! For some reason the onions were really bad! Used a mix of home made chicken stock and commercial beef bone broth for the ‘stock’ which turned out quite well. I like mine a little thicker so I didn’t put in all the required stock! The soup sort of sets in the fridge, not a jelly but not liquid. Maybe a really runny paste which goes more liquid when heated and tastes great!
Thanks for the recipe!
I prepared this soup yesterday and its really delicious 😋
That’s amazing Beatrice! I am glad that you enjoyed it!! N x
Hi, I’m making this recipe tomorrow for the first time, I’ve never made a French Onion soup before either.
I am just wondering if anyone has tried it both ways regarding the preparation of the caramelised onions and if so which way do you think worked out best?
Also I got the Mimi’s brand beef stock, I’m hoping that is a superior brand..
Any feedback welcomed, many thanks.
Made this tonight and it was a hit. I swapped the white wine with shaoxing wine because it was what I had on hand. Also added a touch of sherry vinegar at the end to balance the sweetness. Will definitely make again.
Thanks for those tips, Joanne!! N x
Made this tonight.
The caramalisation of the onions took a little while and a lot of stirring, but the end result is fantastic. BUT… make sure you have the toasted cheese bread with it. It makes the dish !!! Yumms. Everything I have made from Nagi’s recipes ares just the best !!!. Oh, and this is the only recipe from Nagi that’s made me cry !!! 😭. 😂😂😂 Gotta love onions !!
Delicious!! Takes some time but it’s super easy. I wonder how well the soup itself would freeze.
It will freeze well Ann! N x
You can make this soup very rich with amazing results using stock liquid that you’ve slow cooked with, and frozen for later. Dilute with water as necessary and to your taste.
Made this tonight.
The caramalisation of the onions took a little while and a lot of stirring, but the end result is fantastic. BUT… make sure you have the toasted cheese bread with it. It makes the dish !!! Yumms. Everything I have made from Nagi’s recipes ares just the best !!!. Oh, and this is the only recipe from Nagi that’s made me cry !!! 😭. 😂😂😂
Might I suggest some goggles??!! 👨🏽🔬🥽👀😹 N x
Can you please do this in cups, tsp, tbsp. I hate having to Google all the conversions. I’m an amateur cook but that would help a lot.
Sorry specifically the butter and onions
100 grams of butter is about 1/4 cup (half a stick in the USA) and the onions are weighed before peeling and slicing so 1.25 kg is about 8 medium onions! Most of my other recipes have a button that lets you swap between weights or cups!! N x
I just made this and omg so yummy and even though it’s a long process I can see my self making it once a week now to take me through
Made this tonight.
The caramalisation of the onions took a little while and a lot of stirring, but the end result is fantastic. BUT… make sure you have the toasted cheese bread with it. It makes the dish !!! Yumms. Everything I have made from Nagi’s recipes ares just the best !!!. Oh, and this is the only recipe from Nagi that’s made me cry !!! 😭. 😂😂😂 Gotta love onions !!
Don’t fret if you can’t find all the ingredients to a tee. The best soups are improvised.
I just winged this using 1L campbells ‘real’ beef stock along with 500ml of bone broth and a couple chicken stock cubes.
I also used 300ml of red wine because I didn’t have white and for the cheese I used the Coles brand ‘Swiss’ cheese on plain white bread that was about to go stale. Tastes just like Gruyère for 1/6th the price?
Turned out phenomenal!!
I have had different French onion soups and I have to say this one knocks them all out of the ballpark. This recipe will be my forever go to French onion soup I just wanted to tell you also I didn’t have white wine so I used dry red wine phenomenal. I have cooked many of your recipes they are all fantastic.
I’m French and we have a tradition to make onion soup on New Year’s day. I have to say this is the best recipe that I have made and will definitely stick to this one in the future!
Dare I say it is better than the one I remember my mother made.
Oh wow!! Big praise! Thanks!! N x