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!
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!
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! 😀
You don’t need luck! 🙂 N x
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.
Perfect Anne!!
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!
Wahoo! Thats great to hear Margarita!!
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.
I haven’t tried it Stephanie, I’ll have to give it a go!
Making it right now – question about how much salt to add during the caramelization phase?
Hi Susan, start with 1/2 tsp and then salt the final soup to taste – N x
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…
Sure can Amanda!
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,
Perfect Lynda, I’m so happy it was a hit!
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
That’s great to hear!!
Thank you for sharing this recipe. Today I made it and everyone loved it.
I visit your site every day. Nice blog. 🙂
I’m so glad it was a hit Radhika!
Thank you very much!
I made french onion soup with this recipe today for my family and everybody loved it.
That’s so great Aden!
Hi Nagi, I am going to make this and I was just wondering how well would it freeze?
Onion soup freezes really well (no bread/cheese). I freeze it in large Ziploc type bags to ensure getting the air out.
The way you captured this receipe is amazing.
I just made this tonight and is is fantastic!! Thank you!!
Thank you!
Looks like a super comforting soup.
It’s so good Anna, you must try it!
Your soup which became my soup .. delicious .. I do it whit a little beat cheese and one slice of with bread in germs … she is my avorite .. for a long time am looked for Onion soupe…and this one has my taste thank you
I’m so glad you love it!!
¡¡¡Qué rica!!!!!!!! mine for next winter.
Yesss! 🙌
Haaa, Haaa, Dozer do not like onions, getting into his eyes, worse for us preparing it. Love this soup and am always taking time and going extra mile but not making is as often as I should. Years ago we were given home made beer let it to aged ( 12 -18 months ). and add it to soup trust me it was soooooo good it would knock your socks of your feet. You are right by saying to use good / best quality stock. Most of time would do mine and than comes onions and thus would go on and on for up to three days. Hard labour but WORTHED. Ok you two Love you and leave you till next time oh and try to be good..!!
Thanks Vera! I can’t promise I’ll be good – but I’ll try! 😘
I just made this soup for dinner with cheesy garlic bread. Absolutely wonderful. All of your recipes are amazing.
I can only eat onions if they are fully cooked and caramelized onions are even better.
Thank you for another delicious meal.
Hi, just a small question. When you dig in to this lovely soup, how do you eat the crouton with out making a mess or getting it all over the place? Perhaps there is no way and you just have to dig in. How do you tackle it?
Regards Carol.
I personally just like to dig right in!!! 😂
Is there a brand of beef broth that you would recommend in the US?