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Slow Cooker French Onion Soup

Rated as 4.65 out of 5 Stars
27

"This is a ridiculously easy soup, especially since it cooks in a slow cooker! When it's been simmering all day, you come home to an amazing aroma and a fabulous meal for a cold winter day."
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Ingredients

5 h 5 m servings 250
Original recipe yields 8 servings

Directions

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  1. Heat butter in a large, heavy pot over medium-high heat; cook and stir onions until they become translucent, about 10 minutes. Sprinkle onions with sugar; reduce heat to medium. Cook, stirring constantly, until onions are soft and browned, at least 30 minutes. Stir in garlic and cook until fragrant, about 1 minute.
  2. Stir sherry into onion mixture and scrape bottom of pot to dissolve small bits of browned food from the pot. Transfer onions into a slow cooker and pour in beef broth. Season to taste with sea salt; stir in thyme and bay leaf. Cover cooker, set on High, and cook 4 to 6 hours. If desired, set on Low and cook 8 to 10 hours.
  3. About 10 minutes before serving, set oven rack about 8 inches from the heat source and preheat the oven's broiler. Arrange bread slices on a baking sheet.
  4. Broil bread slices until toasted, 1 to 2 minutes per side.
  5. Combine Gruyere, Emmental, Parmesan, and mozzarella cheeses in a bowl, tossing lightly. Fill oven-safe soup crocks 3/4 full of onion soup and float a bread slice in each bowl. Top with about 2 tablespoons of cheese mixture per serving.
  6. Place filled bowls onto a baking sheet and broil until cheese topping is lightly browned and bubbling, about 2 minutes.

Footnotes

  • Cook's Note:
  • You do not HAVE to caramelize the onions, you CAN simply melt the butter in your crock, add the onions to coat them and then add all the ingredients and cook. HOWEVER, caramelizing the onions makes for a much much better soup!!!! :) If you like, simply put all the options out on the table and let people make their own! This seems to be the popular method when I have a craft night. People can make their own decisions about what they want in or on their soup!
  • Easy Cleanup
  • Try using a liner in your slow cooker for easier cleanup.

Nutrition Facts


Per Serving: 250 calories; 14.7 17.5 11 38 596 Full nutrition

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Reviews

Read all reviews 251
  1. 330 Ratings

  2.  
    Rated as 5 out of 5 Stars
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    Rated as 4 out of 5 Stars
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    Rated as 3 out of 5 Stars
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    Rated as 2 out of 5 Stars
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    Rated as 1 out of 5 Stars
Most helpful positive review

I give this recipe 4 starts simply due to the prep work this particular one entails. The soup tasted amazing! However, for ease of cooking, here are my tweaks: First, I sliced the onions, and to...

Most helpful critical review

Even more ridiculously easy: Caramelize the onions in the, lightly-oiled, crock pot (no butter, sugar or sherry needed, just time), add 4-6C beef stock (what's the point of low-sodium if you're ...

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I give this recipe 4 starts simply due to the prep work this particular one entails. The soup tasted amazing! However, for ease of cooking, here are my tweaks: First, I sliced the onions, and to...

Excellent! I followed this recipe to the letter (with the exception of substituting the Gruyere and Emmental with provolone and Swiss) and the soup was to weep for. The smell drove us mad all da...

This is one of the better slow-cooker recipes I've tried. Do take the time to carmalize the onions - the fond makes a lot of difference. Whatever else you do, please do not use 'cooking' sherry,...

This is delicious but since you already spent 40 minutes cooking the onions on the stove and they are already nice and soft, why not just leave it on the stove and add the broth to that pot and ...

This is a great recipe. I couldn't find Emmental so I subbed in Swiss. If you put the bread right in the soup it kind of soaks it up and turns soggy so you can coop that right up with your spo...

Even more ridiculously easy: Caramelize the onions in the, lightly-oiled, crock pot (no butter, sugar or sherry needed, just time), add 4-6C beef stock (what's the point of low-sodium if you're ...

Hi - very very good and easy.

I made this for the 2nd time last night. It's so easy and elegant! This time I used the crockpot to caramelize 3-4lbs sweet onion with 1/2 cup butter and tsp sea salt for six hours (on high).......

WOW! I carmelized my onions early this morning. (took about an hour). I wouldn't skip this step - IT IS what makes the soup. You just can't duplicate that flavor! Also do NOT skip the sherr...