- Prep Time: 15 minutes
- Cook Time: 6-8 hours (low); 3 hours (high)
- Servings: 6 - 8
- Course: Soups & Salads
French onion soup is flavorful and hearty. Simply prepare the soup in a lined slow cooker to warm and allow flavors to meld, and you’ll have a comforting and delicious French Onion Soup.
Reynolds Kitchens® Tips
Reynolds Kitchens tip
Get the same flavorful and hearty soup but from your slow cooker! Line your slow cooker with a slow cooker liner to ensure those sweet, caramelized onions don’t stick. Plus, there’s no sticky mess to clean up when you are done!

Ingredients
- 5 tablespoons unsalted butter
- 5 large yellow onions, sliced (1/4-inch-thick slices)
- 1 tablespoon brown sugar
- 3 sprigs fresh thyme
- Pepper, to taste
- 3 tablespoons all purpose flour
- 1/4 cup soy sauce
- 2 cups chicken stock
- 2 cups beef stock
- 1/2 pound grated Gruyere cheese
- 1 loaf Sourdough bread (optional)
Directions
Step 1
LINE your 5- to 6-quart slow cooker with a Reynolds® Slow Cooker Liner.
Step 2
MELT butter in a large pot over medium heat. Add the onions, brown sugar, thyme and pepper and cook, stirring frequently, until the onions are very soft and caramelized, about 25 minutes.
Step 3
ADD flour, stir to evenly coat onions.
Step 4
Remove from heat and stir in soy sauce.
Step 5
ADD caramelized onion mixture into slow cooker. Add the beef and chicken stocks, cover with lid, set slow cooker to high heat and cook for 3 hours, or until soup is hot.
Step 6
REMOVE and discard thyme sprigs.
Step 7
LADLE into bowls and top with cheese. Serve with sourdough bread (optional).
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