Slow Cooker French Onion Soup Recipe

This Slow Cooker French Onion Soup Recipe is about to be your new favorite way to make soup! Along with homemade mac n’ cheese, French onion soup is one of my favorite things to eat when the weather gets colder.

Not only does it warm you up, but it’s also extremely hearty and filling.

You may think that a lot of work goes into making French onion soup, but this isn’t always the case.

I made this fantastic recipe for a big batch of onion soup that you can freeze in portions to use later.

Serve this with a glass of lovely red wine and salad and voilà… a romantic meal.

This slow cooker french onion soup recipe makes 16 large servings so if you are serving this before a meal reduce the amount of soup in your bowl.

Slow Cooker French Onion Soup Recipe

Slow Cooker French Onion Soup is the classic onion soup recipe done in your crock pot! 

Course Main Course
Cuisine French
Keyword Slow Cooker French Onion Soup Recipe
Prep Time 35 minutes
Cook Time 8 hours
Total Time 8 hours 35 minutes
Servings 16
Calories 320 kcal


  • 6 lbs onions sliced
  • 1 ⁄4 cup butter
  • 14 cups beef stock
  • 1 ⁄2 teaspoon Worcestershire sauce
  • 1 bay leaf
  • 1 ⁄4 teaspoon thyme
  • salt and pepper


  • 2 tablespoons sherry wine optional
  • 2 slices toasted crusty bread
  • 2 tablespoons grated Parmesan cheese
  • 1 ⁄4 cup shredded Gruyere cheese


  1. Over medium heat saute the onion in butter until soft and translucent and caramel color. Make this in 3 batches.
  2. Place onions in slow cooker.
  3. Deglaze cooking skillet with some of the beef stock; this is the secret to that taste.
  4. Add to slow cooker along with the remaining beef broth (your own homemade or powdered mixed with boiling water).
  5. Add Worcestershire sauce, thyme and bay leaf.
  6. Cover; cook on High for 4 hours or on low for 6-8 hours.
  7. Add salt and pepper to taste. Remove bay leaf.
  8. Divide soup into appropriate containers.
  9. Seal and freeze.
  10. When ready to enjoy your French Onion Soup.
  11. Remove from freezer and place in a microwave dish with 2 tbsp sherry; heat for 5 minutes.
  12. Add Parmesan cheese to your onion soup bowl. Place one slice of toasted bread over the cheese. Fill bowl with soup.
  13. Top with shredded Gruyère cheese.
  14. Place under broiler to melt your cheese.

Tip: When adding your ingredients to the slow cooker make sure they are all hot.

Use the processor to slice your onions. I once read “If I use my food processor just to make onion soup it will be worth the cost”.

Bon Appettit!

Up Next: 

Cabbage Sausage and Potato Soup Recipe

Be sure to Follow Foodgasm Recipes on Pinterest for more great recipes!