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Slow Cooker French Onion Soup

This slow cooker French Onion Soup is the perfect winter meal! It’s packed with flavor, and so easy to make. Just throw all the ingredients in your slow cooker, and let it do its thing. You’ll end up with a delicious, hearty soup that will warm you from the inside out.

 Slow Cooker French Onion Soup

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Slow Cooker French Onion Soup

Winter brings the hot soups that warm you from the inside out. French onion soup warms us from the inside out and fills us up with warm bread and cheese. It’s especially great for a budget-friendly meal or a day when you feel like eating lighter. If you are looking for something a bit heavier you should check out our bacon cheeseburger soup.

This french onion soup is a great starter when having friends over for supper, or for a light meal before heading out.

What you need:

How to make Slow Cooker French Onion Soup

The first thing you need to do is slice your onions. I like to slice mine into circles, but slice them however you’d like, slicing them thinly.

Melt your butter in a frying pan over medium heat, with your brown sugar. Toss in all your onions, cover them and let them sit for 5 minutes. Then toss them, cover them, and sit for 5 minutes. Repeat for 20 minutes. You want your onions tender.

Slow Cooker French Onion Soup

Once your onions are tender dump them, the melted butter, and everything into your slow cooker.

Add your beef broth, bay leaf, Worcestershire sauce, balsamic vinegar, thyme, and garlic to your slow cooker.

 Slow Cooker French Onion Soup

While you’re waiting on your soup to cook, slice your french bread, thick. Grate your cheese, we use mozzarella because we have it.

After 4-5 hours on low your french onion soup is cooked and ready to move on to the next step. Dishing it into ramekins.

Top with a slice of French bread, and grated cheese.

 Slow Cooker French Onion Soup

I placed our ramekins on a cookie sheet to make them easier for handling. Broil in your oven. If you use High, watch it closely! You want your cheese to melt and brown not burn.

These are also really good for saving them for later. Great for single-serve heating up the next. And I always find soup so much better the next day, chili too.

 Slow Cooker French Onion Soup

I don’t feel guilty making a pot of crock pot french onion soup for myself once in a while that I can reheat multiple times a week to have lunch for myself.

Slow Cooker French Onion Soup

Slow Cooker French Onion Soup

Yield: 10
Prep Time: 10 minutes
Cook Time: 20 minutes
Inactive Time: 3 hours
Total Time: 3 hours 30 minutes


  • 3 large white onions, sliced
  • 3 tablespoons butter
  • 2 tablespoons brown sugar
  • 4 cups beef broth
  • 1 tbsp Worcestershire sauce
  • 1 clove garlic, minced
  • ⅓ cup balsamic vinegar
  • 1 tsp dried Thyme
  • 1 Bay leaf
  • french bread
  • 1 cup of shredded Mozzarella


  1. In a large non-stick pan, cook onions, butter and brown sugar over medium low heat until golden and caramelized.
  2. Empty the pan into the slow cooker along with remaining ingredients except bread and cheeses.
  3. Cook on low for 4-5 hours.
  4. Remove and discard bay leaf and ladle the soup into bowls. Top with bread slices and cheeses. Broil until cheese is melted and browned.
Nutrition Information:
Serving Size: 1 grams
Amount Per Serving: Unsaturated Fat: 0g

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