Crockpot French Onion Soup

This Crockpot French Onion Soup is a rich and savory recipe, which includes yellow onions and Gruyere cheese. It’s a restaurant-quality dish, ready in about 7 hours and 45 minutes.

Crockpot French Onion Soup Ingredients

• 2 tablespoons unsalted butter, melted
• 3 pounds yellow onions, thinly sliced (about 6 medium onions)
• 4 garlic cloves, minced (about 4 teaspoons)
• 1 tablespoon fresh thyme leaves (or 1 teaspoon dried thyme)
• 1 1/2 teaspoons kosher salt, plus more to taste
• 1/4 teaspoon ground black pepper
• 4 cups low-sodium beef broth (1 quart)
• 1/2 cup dry white wine (such as Sauvignon Blanc)
• 8–12 slices French bread, 1/4-inch thick
• 3 tablespoons extra-virgin olive oil
• 1/2 cup shredded Gruyere cheese

How To Make Crockpot French Onion Soup

1. Caramelize the onions: In a 6-quart slow cooker, combine butter, sliced onions, garlic, thyme, salt, and pepper. Cover and cook on high for 5 to 7 hours, stirring occasionally, until onions are soft and caramelized.
2. Add broth and wine: Stir in the beef broth and white wine. Cover and cook on high for an additional 30 minutes.
3. Prep the bread: While the soup finishes, preheat the broiler and position the oven rack about 6 inches from the top. Arrange bread slices on a baking sheet, brush both sides with olive oil, and broil for 2–3 minutes per side until golden. Watch closely to avoid burning.
4. Assemble and broil: Divide the finished soup among 4 oven-safe bowls or ramekins. Top each with 2–3 slices of toasted bread and sprinkle about 2 tablespoons of Gruyere cheese on top.
5. Broil and serve: Place the bowls on a baking sheet and broil for about 2 minutes until the cheese is melted and bubbling. Sprinkle with extra salt and pepper if desired. Serve immediately.

Recipe Tips

• What onions are best for French onion soup? Yellow onions are ideal for their balanced flavor and sweetness after caramelizing.
• Can I substitute the wine? Yes, you can omit it or use a splash of apple cider vinegar or white grape juice for acidity.
• What cheese can I use instead of Gruyere? Swiss or Emmental cheese are good backups, though Gruyere has the best flavor.
• How to avoid burning under the broiler: Keep a close eye and rotate the pan for even browning.
• How to get deep caramelization: Stir the onions every hour and allow the full 7 hours if you prefer a deeper, richer flavor.

What To Serve With French Onion Soup

This soup is rich enough to stand alone but pairs well with:

• Mixed greens salad with vinaigrette
• Roasted asparagus or green beans
• A charcuterie board
• Red wine or sparkling water
• Extra crusty bread or crostini

How To Store French Onion Soup

Refrigerate: Store leftover soup (without bread or cheese) in an airtight container for up to 4 days. Keep bread in a separate container at room temperature.

Freeze: Freeze the soup in freezer-safe containers for up to 6 months. Thaw in the refrigerator overnight.

Reheat: Warm on the stovetop or microwave, then top with bread and cheese and broil as directed.

French Onion Soup Nutrition Facts

• Calories: 593 kcal
• Carbohydrates: 80g
• Protein: 21g
• Fat: 20g
• Saturated Fat: 7g
• Trans Fat: 0.2g
• Cholesterol: 27mg
• Sodium: 1774mg
• Potassium: 950mg
• Fiber: 7g
• Sugar: 17g
• Calcium: 264mg
• Iron: 5mg

Nutrition information is estimated and may vary based on ingredients and cooking methods used.

FAQs

Can I use vegetable broth instead of beef broth?
Yes, vegetable broth works for a vegetarian version, but it may be less rich in flavor.

Do I need oven-safe bowls?
Yes, to broil the cheese topping. Otherwise, toast bread with cheese separately and place it on top before serving.

Can I make this soup without wine?
Absolutely. It will still taste great with just broth and seasonings.

What’s the best bread to use?
French baguette is traditional, but any crusty bread works well.

Can I caramelize the onions on the stove instead?
Yes, if you want more control over the caramelization process, sauté them on low for 30–40 minutes first.

Try More Recipes:

• Crock Pot Orzo Soup
• Crock Pot Nacho Soup
• Crock Pot Mushroom Wild Rice Soup

Crockpot French Onion Soup

Recipe by Robert Course: SoupsCuisine: AmericanDifficulty: Easy

Servings

5

servings

Prep time

15

minutes

Cooking time

7

hours 

30

minutes

Calories

593

kcal

This slow cooker version of the classic French onion soup is rich, cheesy, and perfect for cozy meals at home.

Ingredients

• 2 tbsp unsalted butter, melted
  

• 3 lbs yellow onions, thinly sliced
  

• 4 cloves garlic, minced
  

• 1 tbsp fresh thyme or 1 tsp dried
  

• 1 1/2 tsp kosher salt
  

• 1/4 tsp ground black pepper
  

• 4 cups low-sodium beef broth
  

• 1/2 cup dry white wine
  

• 8–12 slices French bread
  

• 3 tbsp olive oil
  

• 1/2 cup shredded Gruyere cheese

Directions

• Combine butter, onions, garlic, thyme, salt, and pepper in slow cooker. Cook on high 5–7 hours.
  
• Add broth and wine. Cook 30 more minutes.
  
• Broil bread slices brushed with olive oil until golden.
  
• Divide soup into oven-safe bowls. Top with bread and cheese.
  
• Broil until cheese is melted and bubbly. Serve hot.