Slow Cooker French Onion Soup
Let this healthy, soothing slow cooker French onion soup cook itself while you’re busy with other things. Make it with bone broth for a boost of collagen.
- Prep Time: 10 minutes
- Cook Time: 20 hours 22 minutes
- Total Time: 20 hours 32 minutes
- Yield: 10 - 12 servings
- Category: Soup
- Method: Slow Cooker
- Cuisine: French
Ingredients
Units
Scale
- 3 pounds yellow onions, peeled and sliced
- 2 tablespoons unsalted butter
- 2 tablespoons olive oil
- 1 teaspoon salt, plus more to taste
- Freshly ground black pepper
- 2 tablespoons balsamic vinegar
- 10 cups beef bone broth or homemade beef bone broth or low sodium beef broth
- 3 tablespoons Sherry, optional
For assembling the soup:
- 6 baguette slices for each bowl
- 1 1/3 to 2 cups grated or shaved Gruyere cheese
- Chopped parsley for garnishing
Instructions
- Place onions in a 6-quart slow cooker. Stir in butter and olive oil. Season with salt and pepper. Cover and cook on low for 12 hours.
- Add balsamic vinegar and beef bone broth into the slow cooker. Add Sherry if using.
- Cover and cook on low for another 6-8 hours.
- Preheat oven to 350°F.
- Portion and ladle the soup and onions into oven-safe bowls and place the bowls on a baking sheet.
- Top each bowl with a slice of toast and a generous amount of grated or shaved Gruyere cheese.
- Bake on a rack in the upper third of the oven for 20-30 minutes or until the cheese is melted.
- Switch oven to broil and broil the soup for 2-3 minutes until the cheese is browned.
- Garnish with chopped parsley and serve warm.
Notes
Recipe adapted from The Kitchn.
Nutrition
- Serving Size: 1
- Calories: 167
- Sugar: 5.3g
- Sodium: 363mg
- Fat: 6.6g
- Saturated Fat: 2.7g
- Trans Fat: 0
- Carbohydrates: 19.7g
- Fiber: 2.8g
- Protein: 6.7g
- Cholesterol: 13mg