Description
A hands-off, slow cooker version of the classic French onion soup—sweet, caramelized onions simmered in rich broth, topped with crusty baguette and melted Gruyère for a cozy, restaurant-quality meal.
Ingredients
4 large sweet onions (Vidalia or yellow), thinly sliced
4 tablespoons unsalted butter
1 tablespoon olive oil
1 teaspoon sugar
4 cloves garlic, minced
8 cups beef or vegetable broth
1 cup dry white wine (or extra broth)
2 teaspoons fresh thyme leaves
Salt and pepper, to taste
1 baguette, sliced
2 cups shredded Gruyère cheese
Instructions
- In a large skillet over medium heat, melt butter with olive oil. Add sliced onions and sugar; cook, stirring often, 15–20 minutes until deep golden and caramelized.
- Stir in garlic and cook 1–2 minutes until fragrant.
- Transfer onions and garlic to the slow cooker. Add broth, wine, thyme, salt, and pepper; stir to combine.
- Cover and cook on Low for 6–8 hours (or High for 3–4 hours).
- About 30 minutes before serving, preheat oven to 400 °F. Arrange baguette slices on a baking sheet and toast 5–7 minutes until golden.
- Ladle soup into oven-safe bowls. Top each with 1–2 toasted baguette slices and a generous handful of Gruyère.
- Broil bowls 2–3 minutes until cheese is bubbly and lightly browned. Carefully remove and serve immediately.
Notes
- For a vegetarian version, use high-quality vegetable broth.
- Omit wine and add a splash of white wine vinegar or lemon juice for acidity.
- Make the soup base up to 3 days ahead and reheat before broiling cheese.
- If you lack oven-safe bowls, broil cheese on a baking sheet then transfer to bowls.
- Sprinkle extra thyme or parsley over the melted cheese for garnish.
- Prep Time: 25 minutes
- Cook Time: 6–8 hours (Low) or 3–4 hours (High)
- Category: Soup
- Method: Slow Cooker
- Cuisine: French
Nutrition
- Serving Size: 1 bowl (about 12 oz)
- Calories: 350
- Sugar: 10g
- Sodium: 900mg
- Fat: 18g
- Saturated Fat: 9g
- Unsaturated Fat: 7g
- Trans Fat: 0g
- Carbohydrates: 30g
- Fiber: 2g
- Protein: 15g
- Cholesterol: 40mg
