French Onion Soup With Mushrooms Recipe

If you’ve ever craved the warmth of a hearty, soul-soothing bowl of French onion soup, you’ll know that nothing compares to the rich depth of flavors it offers. But what if we added a little twist to the classic recipe? That’s where French Onion Soup with Mushrooms comes in – a beautiful variation that combines the savory sweetness of caramelized onions with the earthy depth of mushrooms. This version gives the traditional soup a deeper, more complex flavor, taking it from just ’comfort food’ to a full-on flavor adventure.

Picture it: a warm, bubbling bowl of onion soup, topped with a golden, crispy layer of cheese and served with toasted baguette slices. Each spoonful is a balance of sweetness, umami, and a slight smokiness from the browned cheese. The mushrooms contribute an additional layer of earthiness that complements the onions perfectly. It’s no longer just the soup we know and love – it’s a celebration of umami and textures in every bite.

In this post, we’re going to dive deep into the French Onion Soup with Mushrooms recipe, exploring the ingredients, the cooking process, expert tips, and more. Whether you’re looking to make this as a starter for an elegant dinner or as a comforting weeknight meal, you’re in for a treat.

French Onion Soup With Mushrooms Recipe

Here’s how you can make a deliciously rich French Onion Soup with Mushrooms from scratch.

Ingredients Needed

To craft the perfect French Onion Soup with Mushrooms, here’s what you’ll need:

For The Soup Base

• Yellow onions: 4 large, thinly sliced (The heart and soul of this soup)
• Cremini or button mushrooms: 2 cups, sliced (Earthy flavor to add depth)
• Garlic: 3 cloves, minced (For that aromatic kick)
• Beef broth: 6 cups (Traditional, but you can also use vegetable broth for a lighter option)
• Dry white wine: 1 cup (Adds acidity to balance the richness)
• Fresh thyme: 2 sprigs (Herbal notes that work wonders with onions and mushrooms)
• Bay leaf: 1 (For that subtle hint of complexity)
• Olive oil: 2 tablespoons (For sautéing the onions and mushrooms)
• Butter: 2 tablespoons (To add richness and silkiness to the broth)
• Salt and pepper: To taste (For seasoning)

For The Toasted Baguette

• Baguette slices: 1 French baguette (Thick, crusty slices for a hearty crunch)
• Olive oil or butter: 2 tablespoons (For brushing before toasting)
• Garlic powder: ½ teaspoon (Optional, but adds a little more flavor to the crust)

For The Topping

• Gruyère cheese: 1 ½ cups, shredded (Classic French choice – gooey, nutty, and melty)
• Parmesan cheese: ½ cup, grated (For an extra layer of richness and depth)

Cooking Instructions

1. Prepare The Onions And Mushrooms

   • Slice the onions thinly and set them aside. Slice the mushrooms as well. The more uniform the slices, the more evenly they will cook.

2. Caramelize The Onions

   • Heat a large soup pot or Dutch oven over medium heat. Add the olive oil and butter. Once melted, toss in the onions and stir to coat them evenly. Sprinkle with a pinch of salt to help them release moisture.
   • Cook for about 20-25 minutes, stirring occasionally, until the onions become soft and golden brown. The goal here is to develop that deep, sweet flavor, so be patient. Don’t rush this step – caramelizing is key to achieving the soup’s signature richness.

3. Cook The Mushrooms

   • Add the sliced mushrooms to the pot and cook them for 5-7 minutes, or until they release their moisture and start to brown. The mushrooms should get nice and tender, absorbing all the savory goodness from the onions.

4. Deglaze The Pot

   • Pour in the white wine, scraping up any browned bits from the bottom of the pot. This is where a lot of the flavor resides. Let the wine reduce by half, about 2-3 minutes.

5. Add The Broth

   • Pour in the beef broth, thyme, and bay leaf. Bring the soup to a gentle simmer, then reduce the heat to low. Let it simmer uncovered for 30-40 minutes. The flavors will meld together, deepening and intensifying as the broth simmers.

6. Prepare The Baguette Toasts

   • While the soup simmers, preheat the oven to 375°F (190°C). Arrange the baguette slices on a baking sheet and brush them lightly with olive oil or melted butter. Optionally, sprinkle with garlic powder for extra flavor.
   • Toast them in the oven for about 10 minutes, flipping halfway through, until they’re golden and crispy.

7. Assemble And Broil

   • Once the soup has simmered and the flavors have developed, remove the bay leaf and thyme sprigs. Taste the soup and adjust seasoning with salt and pepper.
   • Ladle the soup into oven-safe bowls. Top each with one or two toasted baguette slices, then generously sprinkle with the Gruyère and Parmesan cheeses.
   • Place the bowls under the broiler for 2-3 minutes, or until the cheese is bubbling, golden, and slightly browned.

Ingredient Insights

• Onions: The key to a successful French onion soup is in the onions. Yellow onions are often used because they have the perfect balance of sweetness and acidity when caramelized. The longer you cook them, the sweeter and more intense their flavor becomes.
• Mushrooms: Adding mushrooms, particularly cremini or button mushrooms, adds an earthy, savory note that enhances the overall depth of the soup. Mushrooms have a natural umami quality, making them a perfect addition to this dish.
• Wine: The dry white wine used in this recipe provides a much-needed acidic balance to the richness of the broth and the caramelized onions. It helps to lift the flavors and add complexity.
• Cheese: Gruyère is the star of French onion soup for a reason. It melts beautifully and adds a nutty, slightly sweet flavor that pairs perfectly with the soup’s richness. A sprinkle of Parmesan brings an extra level of depth and saltiness.

Expert Tips

• Be patient with the caramelizing process: The slow cooking of the onions is crucial for developing that deep, rich flavor. Don’t rush it. Stir them occasionally, but let them take their time to turn golden brown and soft.
• Use a mix of broths: If you want a slightly lighter flavor, try using half beef broth and half vegetable broth. This keeps the richness but adds a more nuanced taste.
• Toast the bread in the soup: For a slightly different take, you can toast the bread directly in the soup before broiling. This ensures the bread soaks up more of the flavorful broth.
• Add a splash of balsamic vinegar: If you want an added layer of complexity, a dash of balsamic vinegar right before serving will enhance the soup’s sweetness and depth.

Recipe Variations

• Vegetarian Option: Simply swap the beef broth for vegetable broth. It still works beautifully, especially with the mushrooms adding their meaty texture and flavor.
• Gluten-Free: Use gluten-free baguette slices for the toasts. You can find excellent gluten-free options, or even make your own.
• Add More Herbs: While thyme is classic, feel free to experiment with other herbs like rosemary or sage for a slightly different flavor profile.
• Cheese Alternatives: If Gruyère is hard to find, try Swiss cheese or a sharp cheddar for a similar meltiness and flavor.

Final Words

French Onion Soup with Mushrooms is an elevated, flavorful twist on the beloved classic. The combination of caramelized onions, savory mushrooms, and melted cheese creates a harmonious balance of textures and tastes that can warm you from the inside out. Whether you’re serving it as a starter or a comforting meal, this soup has a timeless appeal that is sure to satisfy.