Description
This Mushroom and Caramelized Onion Soup with Cheesy Toasties is a comforting and flavorful dish featuring deeply caramelized onions and sautéed cremini mushrooms simmered in a rich beef broth. Topped with golden, cheesy baguette toasties made with Gruyère and Parmesan, this soup is perfect for cozy dinners or special occasions.
Ingredients
Scale
For the Soup:
- 4 tablespoons unsalted butter
- 4 large yellow onions, thinly sliced
- 2 cloves garlic, finely chopped
- 2 bay leaves
- 2 sprigs fresh thyme
- 1 cup dry white wine
- 1/4 cup all-purpose flour
- 8 cups beef broth
- Salt and black pepper, to taste
For the Mushrooms:
- 1 tablespoon unsalted butter
- 1 tablespoon olive oil
- 1 clove garlic, finely chopped
- 24 ounces cremini mushrooms, quartered
- 1 teaspoon chopped fresh thyme
- Salt and black pepper, to taste
For the Toasties:
- 1 baguette, sliced into rounds
- 8 ounces freshly grated Gruyère cheese
- 1/2 cup freshly grated Parmesan cheese, plus more for garnish
Instructions
- Caramelize Onions: Melt 4 tablespoons of butter in a large pot over medium heat. Add the thinly sliced onions, bay leaves, fresh thyme sprigs, and a pinch of salt. Cook slowly, stirring frequently, for 30 to 40 minutes until the onions are deeply caramelized and golden brown.
- Add Garlic: Stir in 2 cloves of finely chopped garlic and cook for 1 minute until fragrant, being careful not to burn the garlic.
- Deglaze with Wine: Pour in 1 cup of dry white wine, scraping the bottom of the pot to release any browned bits. Let the wine simmer until mostly evaporated, infusing the onions with depth of flavor.
- Add Flour: Sprinkle 1/4 cup of all-purpose flour over the mixture, stirring well to combine. Cook for 2 minutes to remove the raw flour taste and help thicken the soup later.
- Add Broth and Simmer: Gradually whisk in 8 cups of beef broth, ensuring no lumps form. Bring the mixture to a boil, then reduce the heat and let it simmer gently for 20 to 25 minutes to meld the flavors.
- Sauté Mushrooms: While the soup simmers, heat 1 tablespoon unsalted butter and 1 tablespoon olive oil in a skillet over medium heat. Add 1 clove of finely chopped garlic and sauté for 30 seconds until fragrant. Add the quartered cremini mushrooms and 1 teaspoon chopped fresh thyme. Cook for 10 to 12 minutes, stirring occasionally, until the mushrooms are browned and tender. Season with salt and black pepper to taste.
- Prepare Toasties: Toast the baguette slices until they are golden brown. Top each slice generously with freshly grated Gruyère cheese and Parmesan cheese. Broil under a hot oven or grill until the cheese is bubbly and lightly browned.
- Serve: Ladle the hot soup into serving bowls. Stir the sautéed mushrooms into the soup or add on top as desired. Place the cheesy toasties on top of the soup or serve on the side. Garnish with extra Parmesan cheese and fresh thyme sprigs for an elegant finish.
Notes
- For a vegetarian version, use vegetable broth instead of beef broth.
- Be patient while caramelizing onions to develop deep flavor; rushing this step can result in less sweetness and color.
- Use day-old baguette for best toasting results.
- Gruyère is preferred for its melting qualities and nutty flavor, but Swiss cheese can be a substitute.
- Adjust seasoning at the end as broth and cheeses add saltiness.
- Prep Time: 20 minutes
- Cook Time: 1 hour 15 minutes
- Category: Soup
- Method: Stovetop
- Cuisine: French
Keywords: mushroom soup, caramelized onion soup, cheesy toasties, cremini mushrooms, French soup, comfort food, Gruyère cheese
