Ingredients
Scale
- 4 large yellow onions
- 2 large sweet onions (Vidalia)
- 6 tablespoons butter
- 4 cups beef broth
- 1.5 cups chicken broth
- ¾ cup apple vinegar
- 1 baguette
- 6 slices Gruyere cheese
Instructions
- Slice all onions into ¼-inch pieces using a mandoline slicer if available.
- Melt butter in a large soup pot over medium-low heat, then add the sliced onions.
- Cook uncovered for about 2 hours, stirring every 10-15 minutes until caramelized.
- Add flour when nearly finished, then pour in apple vinegar and cook until richly brown.
- Combine broths and herbs; let simmer for 45 minutes.
- Preheat oven to 350°F, slice baguette, brush with olive oil, and toast for about 5 minutes.
- Top baguette slices with Gruyere cheese and bake at 450°F until bubbly.
- Serve soup warm topped with toasted baguettes.
- Prep Time: 20 minutes
- Cook Time: 120 minutes
- Category: Main
- Method: Simmering/Baking
- Cuisine: French
Nutrition
- Serving Size: 1 bowl (240ml)
- Calories: 310
- Sugar: 9g
- Sodium: 820mg
- Fat: 17g
- Saturated Fat: 10g
- Unsaturated Fat: 5g
- Trans Fat: 0g
- Carbohydrates: 30g
- Fiber: 3g
- Protein: 8g
- Cholesterol: 40mg