Description
A rich and comforting vegetarian French onion soup featuring deeply caramelized onions, a flavorful homemade mushroom and vegetable broth, and a cheesy, toasted bread topping broiled to golden perfection. Perfect for a cozy meal that highlights classic French flavors without using meat.
Ingredients
For Caramelized Onions
- 2 tablespoons butter
- 3 pounds yellow onions (about 5 medium)
- 1 teaspoon kosher salt
For Homemade Broth
- 2 tablespoons butter
- 8 ounces mushrooms, sliced
- 1 carrot, cut in half lengthwise and into large chunks
- 2 celery ribs, cut into large pieces
- 6 garlic cloves, smashed and peeled
- 9 cups water, divided
- 2 tablespoons tomato paste
- 1 teaspoon garlic powder
- 1 teaspoon onion powder
- 1 teaspoon vegan Worcestershire sauce (store-bought or homemade substitute)
- 2 teaspoons kosher salt
For Soup Assembly and Topping
- 1/2 cup dry sherry (or dry white wine)
- 1 tablespoon flour
- 6 slices Swiss or Gruyere cheese (or shredded equivalent)
- 6 tablespoons grated Parmesan cheese
- 6 large or 12 small slices bread, sliced about 1/2 inch thick
Instructions
- Caramelize the Onions: Thinly slice the onions about 1/8 inch thick using a French cut method. In a large soup pot, heat 2 tablespoons butter over medium-high heat. Add the onions and sauté for 8 to 10 minutes, stirring often, until they become very soft with slight browning at the bottom. Reduce heat to medium-low and stir in 1 teaspoon kosher salt. Continue cooking the onions slowly for 40 to 45 minutes, stirring every 5 to 10 minutes and adjusting heat as needed to avoid burning. The onions will turn from raw to golden to very dark brown and reduce in volume significantly.
- Prepare the Broth: Slice mushrooms. Wash and chop the carrot and celery into large chunks. Smash and peel garlic cloves. In a separate pot, heat 2 tablespoons butter over medium heat. Add mushrooms and sauté for 6 to 7 minutes until browned. Add 8 cups of water, the salt (2 teaspoons), carrot, celery, garlic, tomato paste, garlic powder, onion powder, and vegan Worcestershire sauce. Bring to a boil then reduce heat and simmer the broth for 30 minutes to develop flavor.
- Combine and Simmer Soup: When the onions are deeply caramelized, pour in the sherry and deglaze the pan by scraping all browned bits from the bottom. Sprinkle the flour over the onions and stir to coat evenly. Strain the homemade broth through a fine sieve, discarding the solid vegetables, and pour the strained broth into the pot with onions. Add the remaining 1 cup of water and bring the soup to a gentle simmer for about 2 minutes to meld flavors.
- Broil the Cheese and Bread Topping: Preheat your oven broiler to high or set the oven to 400°F. Ladle the soup into 6 oven-safe bowls or ramekins. Top each bowl with a slice of bread (about 1/2 inch thick), then place one slice of Swiss or Gruyere cheese on top, and sprinkle with 1 tablespoon of grated Parmesan cheese. Place under the broiler for 1 to 3 minutes, or bake for about 20 minutes, until the cheese melts and turns golden brown. Serve immediately, being careful as bowls will be hot.
Notes
- For a make-ahead tip, caramelize onions and prepare broth in advance, then reheat before finishing soup.
- Use dry sherry or dry white wine for deglazing to add depth of flavor. Avoid sweet wines.
- For vegan versions, ensure cheese substitutes align or omit cheese entirely.
- Adjust salt to taste depending on the saltiness of cheese used in the topping.
- Use sturdy, crusty bread like baguette or sourdough for best topping texture.
- Prep Time: 20 minutes
- Cook Time: 1 hour
- Category: Soup
- Method: Stovetop
- Cuisine: French
