Description
This classic French Onion Soup is rich, comforting, and packed with deep caramelized onion flavor. Topped with crispy baguette slices and melty Gruyère cheese, it’s a cozy and satisfying dish perfect for any occasion.
Ingredients
For the Soup:
- 4 large onions, thinly sliced (yellow or sweet onions work best)
- 2 tablespoons unsalted butter
- 1 tablespoon olive oil
- 2 cloves garlic, minced
- 1 teaspoon sugar (optional, for faster caramelization)
- 6 cups beef broth (low sodium preferred)
- 1 teaspoon dried thyme (or 2 sprigs fresh thyme)
- 1 bay leaf
- Salt and black pepper, to taste
For the Topping:
- 1 baguette, sliced into 1/2-inch rounds
- 1 cup grated Gruyère cheese (or Swiss/Provolone as alternatives)
- Butter, for toasting baguette slices
Instructions
In a large pot or Dutch oven, melt the butter with the olive oil over medium heat. Add the sliced onions and stir to coat. Sprinkle with a pinch of salt and the sugar (if using). Cook, stirring occasionally, for 25–30 minutes, or until the onions are deeply golden and caramelized. Reduce heat if they begin to stick or brown too quickly.
Stir in the garlic and cook for 1 minute. Simmer until the liquid reduces by half, about 2–3 minutes.
Pour in the beef broth, then add the thyme and bay leaf. Bring to a boil, then reduce the heat and simmer for 20–25 minutes. Season with salt and pepper to taste. Remove the thyme sprigs and bay leaf before serving.
While the soup simmers, preheat your oven to 400°F (200°C). Lightly butter the baguette slices and place them on a baking sheet. Toast in the oven for 5–7 minutes, or until golden and crisp. Remove from the oven, sprinkle each slice with Gruyère cheese, and return to the oven. Broil for 2–3 minutes, or until the cheese is melted and bubbly.
Ladle the soup into oven-safe bowls. Place 1–2 cheese-topped baguette slices on top of each bowl. Broil the bowls in the oven for 2–3 minutes, or until the cheese is golden and bubbly. If oven-safe bowls aren’t available, serve the soup with the cheese baguettes on the side. Garnish with fresh thyme or parsley, if desired, and serve hot.
Notes
- For a vegetarian version, swap beef broth for vegetable broth and add a splash of soy sauce for extra depth.
- Caramelizing the onions slowly is key to developing the soup’s rich flavor, so be patient.
- Leftovers can be stored in the refrigerator for up to 3 days and reheated on the stovetop.