Description
This classic French Onion Soup recipe features deeply caramelized onions, simmered in a savory beef or vegetable broth with Worcestershire sauce and balsamic vinegar, topped with toasted croutons and molten provolone cheese. The soup is finished under the broiler for a golden, bubbly cheese crust, delivering a comforting and rich taste perfect for cozy meals.
Ingredients
Scale
Soup Base
- 4 Large Onions (Thinly Sliced)
- 4 Tablespoons Unsalted Butter
- 6 Cups Beef or Vegetable Broth
- 1 Teaspoon Worcestershire Sauce
- 1 Tablespoon Balsamic Vinegar
- 2 Bay Leaves
- 1 Teaspoon Dried Thyme (or 1 Tablespoon Fresh Thyme Leaves)
- Salt and Pepper (to taste)
Toppings
- Croutons or Baguette Slices
- Provolone Cheese Slices
Instructions
- Caramelize Onions: In a large pot, melt the unsalted butter over medium heat. Add the thinly sliced onions and cook until they become soft and caramelized, stirring occasionally. This process will take about 25-30 minutes, developing a deep golden color and sweet flavor.
- Add Broth and Seasonings: Once the onions are nicely caramelized, add the beef or vegetable broth, Worcestershire sauce, balsamic vinegar, bay leaves, dried thyme, salt, and pepper to the pot. Stir well to combine all the ingredients evenly.
- Simmer Soup: Bring the soup to a boil, then reduce the heat to low and let it simmer gently for 15-20 minutes. This allows the flavors to meld together and deepen, resulting in a rich and savory broth.
- Prepare Bowls: Remove the bay leaves from the pot. Ladle the hot soup into individual oven-safe bowls or crocks, filling each about three-quarters full to leave room for toppings.
- Add Croutons: Place a few toasted croutons or baguette slices atop the soup in each bowl, forming a single even layer that will hold the cheese.
- Layer Cheese: Arrange 2-3 slices of provolone cheese over the croutons, covering the entire surface to ensure maximum melt and browning.
- Broil Cheese: Transfer the bowls to the broiler and cook for 2-3 minutes, or until the cheese is fully melted, bubbly, and lightly browned. Watch carefully to prevent burning.
- Remove Carefully: Use oven mitts or kitchen towels to carefully remove the hot bowls from the broiler, as they will be very hot.
- Serve and Garnish: Let the soup cool slightly for a couple of minutes. Garnish with fresh thyme leaves or parsley if desired, then serve while the cheese is gooey and the soup is piping hot.
Notes
- Caramelizing the onions slowly is key to developing the soup’s deep flavor; avoid rushing this step by increasing heat.
- Use oven-safe bowls or crocks for broiling the cheese topping to prevent damage and for safe handling.
- Broil the cheese under close supervision to achieve a perfect golden crust without burning.
- Vegetarian option: Use vegetable broth and omit Worcestershire sauce or substitute with a vegetarian alternative.
- Leftover soup can be stored in the refrigerator for up to 3 days but add croutons and cheese just before serving to maintain texture.
