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)
-
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!
Katherine Kelley says
Nagi, making this now & almost done so cannot wait to eat it! Not sure you have it there, but here in the US we have a product “Better Than Bouillon” & it’s better than any chicken or beef broth I’ve made myself or purchased in a store. I keep sampling the broth in this soup & yum!!! Thank you for your recipes, the ones I’ve tried have all been great.
Christopher says
Katherine! Don’t give away the secret! (I actually forgot about that jar of Better Than Bouillon but will be using it now; appreciate the reminder).
Ana says
Oh.. my … god! Nagi you have converted me. I once had French onion soup so bad a restaurant I assumed that’s how it all tasted. Well I was so very wrong. Thanks for the tip on buying the premium stock. I would have never seen those brands if it wasn’t for you!! I’m making another batch today, can’t get enough 🙂 thank you
Rachel A. says
This soup was amazing! I made it today on the stove top and my sis in law made it in the crockpot. Another fabulous recipe….again I threw out my old recipe.
Heidi says
Just made the French onion soup, it was soooo good.
Gillian says
Can I just omit the flour to make this gluten free or would I need to substitute with an alternative?
Nagi says
Hi Gillian, use 1 tbls cornflour as a gluten free sub 🙂 N x
Gillian says
Thank you – made this last night and it was yum
Deb says
This soup is devine! I absolutely love french onion soup but it is a bit of a labour of love so admittedly don’t make it very often. I’m so glad I came across this recipe when Miss 7 asked for it. Being vegan I used Maggie Beer’s vegetable stock and it worked beautifully. Definitely my go to from now on!
Nagi says
I’m so glad you loved it Deb!! N x
Elizabeth says
Amazing…i added a pinch of brown sugar and a few dashes of worscher sauce. Toasted borh sides of bread with butter. Piles of cheese and made cheese bread then sliced and put in soup.
Linda says
Hi…I have also carmelized onions in the oven, sliced and sprinkledvwith oil . Also works
Don’t have to watch it ad much.
Nagi says
Delish Elizabeth! N x
Brigette Paterson says
Mmmmm… absolutely delicious!
It’s so much easier to do the cheesy croutons your way. I just used regular cheddar.
On reading your comments I decided to finally attempt making my own beef stock and WOWSERS – what a difference!!!
I read the ingredient list on beef stock cubes … it doesn’t even contain any beef!
I’ve made this twice in two weeks – sometimes all I can eat is soup due to my autoimmune disease which causes huuuuuge ulcers on my tongue and all down my throat and it’s so painful to eat anything solid – so thank you Nagi.
Nagi says
I’m so glad you love it Brigette, that’s great to hear! N x
Sabrina says
I’m French and I absolutely love this soup !
Nagi says
That’s awesome, thanks so much for letting me know Sabrina! N x
Erin Dumouchel says
Best French onion soup recipe. The search is over! I make this soup atleast once a month… I sub in Guinness though… mmmm… the wine does make it a little richer though…. sonic really like that aspect.
Thaaaaaanks so much for sharing!
Andy says
Going to give this one a go tomorrow, prepared onions in advance. Other versions I’ve made call for the cheese rind to go in and out with the bay leaves so will do that, otherwise will follow this recipe. Wish me luck! 😀
Nagi says
You don’t need luck! 🙂 N x
Anne says
I love this soup! I’ve made it three times. I can only eat onions if they are fully cooked and caramelizing them just brings out their yumminess. I have it with a side a cheesy garlic toast to dip in the soup.
Nagi says
Perfect Anne!!
Margarita says
Oh. My. Goodness! What an easy recipe to follow and it tasted great! It was my very first time to make French onion soup and what a success! Nagi! Your recipe is awesome! I’m making it again to impress my friends!
Nagi says
Wahoo! Thats great to hear Margarita!!
Stephanie says
Hi Nagi, have you tried the bone broth powders and concentrates sold at health food shops, in your recipes? I have a beef broth concentrate (made in QLD) that is natural however it’s white cloudy in colour rather than transparent brown. I drink the broth by itself but haven’t yet tried it in recipes to replace beef stock cubes.
Nagi says
I haven’t tried it Stephanie, I’ll have to give it a go!
Susan says
Making it right now – question about how much salt to add during the caramelization phase?
Nagi says
Hi Susan, start with 1/2 tsp and then salt the final soup to taste – N x
Amanda Kowal says
Absolutely love this soup and make it all the time.
was wondering if the broth(bread and cheese excluded) can be made in advance and frozen so that I can take it out the day I need it, like a dinner party…
Nagi says
Sure can Amanda!
Lynda Wilson says
Hi Nagi, I made this soup yesterday for a dinner party. In the morning I made it up to Step 3 (but with only 1/3 of the stock), refrigerated and then added the rest of the stock, simmered etc when the guests arrived. So simple. Everyone raved about it. Definitely a keeper! Thank you,
Nagi says
Perfect Lynda, I’m so happy it was a hit!
ARCHANA MATCHA says
Thank you so very much for posting these fabulous recipes . I made this soup yesterday and it was a smash hit !!! Looking forward to trying out more of your recipes … Loads of Love
Nagi says
That’s great to hear!!
Radhika Sharma says
Thank you for sharing this recipe. Today I made it and everyone loved it.
I visit your site every day. Nice blog. 🙂
Nagi says
I’m so glad it was a hit Radhika!
Aden says
Thank you very much!
I made french onion soup with this recipe today for my family and everybody loved it.
Nagi says
That’s so great Aden!