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–+ servings
Benjamin

Rich & Savory French Onion Mushroom Soup – A Comfort Food Classic!

This French Onion Mushroom Soup combines the deep, caramelized sweetness of onions with the rich, earthy flavors of mushrooms, all simmered in a savory broth and topped with crispy baguette slices and melty Gruyère cheese. It’s the ultimate comfort food, perfect for cozy nights or impressing dinner guests with its gourmet, restaurant-quality taste.
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Prep Time 10 minutes
Cook Time 50 minutes
Total Time 1 hour
Servings: 4 servings
Course: Soup
Cuisine: French
Ingredients Method Notes

Ingredients
  

  • Unsalted butter
  • Olive oil
  • Yellow onions thinly sliced
  • Cremini mushrooms sliced
  • Garlic cloves minced
  • Fresh thyme leaves
  • Dry white wine
  • All-purpose flour
  • Beef broth
  • Bay leaf
  • Salt and black pepper
  • Baguette slices
  • Gruyère cheese grated

Method
 

  1. Caramelize the onions in butter and olive oil over medium-low heat, stirring frequently until deeply golden.
  2. Add mushrooms and cook until tender, then stir in garlic and thyme.
  3. Deglaze the pot with white wine, scraping up any browned bits from the bottom.
  4. Sprinkle flour over the mixture and stir to coat, then slowly add beef broth and a bay leaf.
  5. Simmer for 20–30 minutes to let the flavors develop. Season with salt and pepper.
  6. Toast the baguette slices under the broiler until golden brown.
  7. Ladle soup into oven-safe bowls, top each with a toasted baguette slice and grated Gruyère.
  8. Broil until the cheese is bubbly and golden, then serve immediately.

Notes

  • Low and slow is key – Properly caramelizing onions takes time but builds incredible flavor.
  • Use quality broth – A rich, homemade beef broth enhances the depth of the soup.
  • For extra creaminess, stir in a splash of heavy cream before serving.
  • Make it vegetarian – Swap beef broth for vegetable broth and use a plant-based cheese.
  • Store leftovers – The soup (without cheese and bread) keeps well in the fridge for 4 days and freezes for 3 months.

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