Slow Cooker French Onion Soup

 Slow Cooker French Onion Soup with loads of flavor, caramelized onions, and mounds of melty CHEESE! 

Slow Cooker French Onion Soup

This weather, it’s messing with my head. I’m sitting here at my desk, doing my blog-homework-email-blogsomemore-takeacookiebreak-thang and all of this sunshine coming through the window is messing with my head. Because I really want to walk outside barefoot and lay on the grass in the sunshine but I know, deep down, that I would regret that. Because even though it looks sunny and yellow and bright outside, it is actually nasty-chilly.

Slow Cooker French Onion Soup

I really want to lay on that grass because it’s semi-greenish and not covered in snow, like it’s supposed to be in January, and it’s driving me craZy with a capital z. In fact it had me 99% deceived for a minute because after a rather pungent aroma of freshly caramelized onions permeated the upstairs and into our bedroom last night, I decided to put the crockpot out on the back porch to do it’s slow cooking thing out where no one would be kept awake by the scent. And this morning when I went out to check on it in my sockless, long sleeveless attire, I took a look outside and thought woah it’s so sunny – it must be warm!


Slow Cooker French Onion Soup
 It is most definitely not warm. Not even a little bit. And my toes haven’t let me forget it.

So even though it’s sun-shiney outside, I know that it’s really miserably cold and that soup is in order – not popsicles. In fact all I want to do is curl up in a blanket and eat french onion soup all day long. But I’ve run out of stomach room so I think I’ll settle for staring at 9hundredandseventeenmillion pictures of french onion soup.

Care to join?

Slow Cooker French Onion Soup

You see all that cheese? It’s ooey-gooey-melty-stretchy-awesomeness and I’m in love with it.

Wanna see it in action??


Slow Cooker French Onion Soup

Slow Cooker French Onion Soup

Slow Cooker French Onion Soup
 Allllllll thaaaaaat CHEEEEEESE.

Slow Cooker French Onion Soup

And while we are on the subject of cheese. I did my research while I was testing this recipe and it appears that the traditional cheese of choice for french onion soup is gruyere – which, if you don’t know already, is totally 100% delicious. But if you haven’t shopped for gruyere, then you might not know that a triangle smaller than my hand is somewhere around like, 11 dollars.

I’m acutely aware that 11 dollar fancy cheese is not in everyone’s everyday soup budget so in honor of all you peeps who, like me, don’t want to spend a small fortune on one ingredient for your dinner, I tried a little something different and went with SWISS. Yeah, swiss cheese. More budget-friendly and still scoring 11 out of 10 in the taste department.

Slow Cooker French Onion Soup

So if you’re a cheese connoisseur or just want to treat yourself because hey, it’s Friday – then by all means get that gruyere and enjoy every little shred of it! If not, know that swiss is a more than acceptable substitute.

Slow Cooker French Onion Soup

Oh my heaven I’ve overloaded you with words today. Gahhh! I’m just gonna shut my yap now.

Slow Cooker French Onion Soup

Slow Cooker French Onion Soup

Slow cooker french onion soup - loads of flavor, caramelized onions, and CHEESE!
Course Soup
Keyword French Onion, soup
Prep Time 30 minutes
Cook Time 4 hours
Total Time 4 hours 30 minutes
Servings 4
Author Tiffany


  • 4 yellow onions, skins removed and thinly sliced into rings
  • 4 tablespoons butter
  • 2 tablespoons minced garlic
  • 8 cups beef broth
  • 1 bay leaf
  • 6 slices crusty french bread
  • 8-12 slices gruyere or swiss cheese


  • Add butter and onion rings to the largest pan/skillet you have and saute over medium-high heat for about 10 minutes or until onions are translucent and start to brown. Cover and cook about 5 minutes longer to let them caramelize a little more.
  • Transfer onions to slow cooker. Add garlic, broth, and bay leaf. Cover and cook on high 3-4 hours or on low 6-8 hours (or up to 10).
  • About 20-30 minutes before serving, preheat oven to 420 degrees. Place slices of bread in a single layer on a baking sheet. Place in preheated oven for about 5 minutes, then flip the bread slices over and return to oven for another 5 minutes or so until bread is dried and crunchy. Set aside.
  • Place oven-safe bowls on the baking sheet. Fill each with soup from the slow cooker. Place 2 slices of swiss cheese (overlapping) on top of the soup so the edges are hanging over the sides of the bowls. Bake about 10 minutes until cheese is melty. Serve with crusty bread and garnish with parsley if desired.

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It’s so dang cold. Right now, everything is covered in a layer of ice. Imma need this soup. Pinned.

Green grass? I’ll take it, it is crazy cold and white out there. This soup would definatly make me feel better though. As would the masses of cheese you added! Yummy and beautiful photos Tiffany.

    I couldn’t be happier to be seeing the green grass right now – we usually have feet of snow right now and I hate the cold! The only good thing is that it gives me a great excuse to make soup for days in a row 😉

To steal a line from Full House, “Have MERCY!” This looks divine for the chilly fall weather we’re having! Yum!

Hello! I love French onion soup and my slow cooker, so I’m happy to have found your recipe! Just one look at those pictures…yum! I recently started my own food blog and used your recipe as basis for my 3rd post :). I hope you don’t mind, I just had to share!

I don’t know how you can caramelize onions in in 15 minutes. I have always used Julia Child’s recipe which takes 15 minutes to steam them, then another half hour or more to stir them until a deep mahogany brown. I suspect that dropping the initial steam step could streamline this a bit, but there is still going to be plenty of prep time

    I haven’t had any issues with this, they always take about 15 minutes for me!

This recipe looks awesome! I’m semi-vegetarian and I would rather not use beef broth. Do you think veggie broth would work as a substitute? I use it all the time when recipes call for chicken broth, but I’ve never subbed it for beef broth. I know Trader Joe’s frozen French Onion soup (which is delicious in a pinch) is vegetarian, so it must be possible to make veg French Onion …

    Miranda, I’m vegan and I do that swap all the time. Although Bisto Gravy (beef and onion varieties) is vegetarian/vegan, at least in the UK, so I add a bit of that too so I can get a beefy flavour.

Hi sorry I know this is an old post but does this freeze well? Thanks 🙂

It call for 4 onion but put in 8 to 10 . It better

This is good. It calls for 4 onions but use 8 at least

TERRIFIC recipe. Soup is fantastic. Did not change a thing.

    So glad that you loved it, Sandy! Thanks for your feedback!

Minor tips:
#1 Take your time with the onion. Low heat. a good hour in the pot.
#2 Deglaze the pan with wine and let it go for a few minutes, before transferring to the slow cooker.

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