Description
A classic French Onion Soup recipe featuring slow-caramelized onions, rich beef and chicken broth, and topped with toasted baguette slices and melted Gruyere cheese. This comforting soup combines deep caramel flavors with a cheesy, crispy finish, perfect for a cozy meal.
Ingredients
Onions and Herbs
- 4 large yellow onions (about 3 pounds)
- 2 large sweet onions (Vidalia)
- 2 sprigs fresh thyme
- 2 bay leaves
Liquids and Broth
- ¾ cup dry white wine (Chardonnay or Pinot Grigio)
- 4 cups beef broth (high quality)
- 1 beef bouillon cube or 1 teaspoon Better Than Bouillon
- 1.5 cups chicken broth
- 1 teaspoon Worcestershire sauce
Other Ingredients
- 6 tablespoons butter
- 3 tablespoons flour (optional)
- Salt and pepper to taste
- 1 baguette
- 3 tablespoons olive oil (optional)
- 6 slices Gruyere cheese
Instructions
- Slice the Onions: Slice the onions into ¼-inch thickness. Using a mandoline slicer is recommended for consistent slices. This size will allow the onions to caramelize evenly without becoming stringy.
- Melt the Butter: In a large soup pot or Dutch oven, melt the butter over medium-low heat. Wait until it starts to foam; this indicates the water has evaporated and the butter is becoming clarified, resulting in a smooth base for cooking the onions.
- Cook the Onions: Add the sliced onions to the pot and toss to coat them in butter using tongs. Leave the pot uncovered and allow the onions to cook slowly. Stir every 10-15 minutes to ensure even caramelization.
- Caramelize the Onions: Continue to cook the onions for up to 2 hours or longer until they are richly brown and sweet. During this process, use a splash of wine and a silicone spatula to deglaze and scrape the browned bits from the bottom of the pot as needed.
- Add Flour and Increase Heat: When the onions are nearly done, sprinkle the optional flour over them and cook for 2 minutes. Add any remaining white wine and increase the heat to medium-high, tossing the onions frequently to avoid burning.
- Add Broth and Seasonings: Pour in the beef broth, chicken broth, Worcestershire sauce, and add the beef bouillon cube (or Better Than Bouillon), along with the bay leaves and thyme sprigs. Bring to a simmer over medium heat and cook for 45 minutes with the lid slightly ajar.
- Preheat Oven and Prepare Baguette: While the soup simmers, preheat your oven to 350°F (175°C). Slice the baguette into ½-inch thick slices. Brush the tops with olive oil if desired and bake for about 5 minutes to toast.
- Top with Cheese: Increase the oven temperature to 450°F (230°C). Place a slice of Gruyere cheese on each toasted baguette slice and return to the oven. Bake until the cheese melts, bubbles, and begins to brown.
- Finish the Soup: Remove the bay leaves and thyme stems from the soup. Taste and adjust seasoning with salt and pepper as needed.
- Serve: Ladle the hot soup into bowls, top each with a cheesy baguette slice, and serve immediately.
Notes
- Using a mandoline slicer ensures uniform onion slices for even caramelization.
- Slow caramelization develops the best flavor; avoid rushing this step.
- The flour is optional but helps to thicken the soup slightly.
- Use high-quality beef broth for the richest taste.
- The choice of white wine and Gruyere cheese significantly impacts the final flavor; avoid subbing on these for best results.
- Vegetarian modifications can be made by substituting vegetable broth and omitting Worcestershire sauce or using a vegetarian version.
- Prep Time: 20 minutes
- Cook Time: 2 hours 35 minutes
- Category: Soup
- Method: Stovetop
- Cuisine: French
