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French Onion Soup with Mushrooms, Extra Herbs & Cheesy Croissant Topping

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A rich and comforting twist on classic French onion soup, featuring savory caramelized onions, earthy mushrooms, fragrant herbs, and a buttery croissant and cheese topping. Perfect for cozy, indulgent meals.

Ingredients

  • 4 large yellow onions, thinly sliced
  • 8 oz mushrooms (cremini or baby bella), sliced
  • 2 tbsp olive oil
  • 2 tbsp butter
  • 3 cloves garlic, minced
  • 2 tbsp all-purpose flour
  • 6 cups beef broth or vegetable broth
  • 1/2 cup dry white wine (optional)
  • 1 tsp fresh thyme, chopped
  • 1 tsp fresh rosemary, chopped
  • 1 bay leaf
  • Salt, to taste
  • Black pepper, to taste
  • 2 croissants, sliced into rounds or halves
  • 1 1/2 cups shredded gruyère or swiss cheese

Instructions

  1. Heat olive oil and butter in a large pot over medium heat.
  2. Add sliced onions and cook, stirring often, for 25–30 minutes until deeply caramelized.
  3. Add mushrooms and cook until they release moisture and turn golden, about 8–10 minutes.
  4. Stir in garlic and cook for 1 minute. Sprinkle in flour and cook for another 1–2 minutes to eliminate the raw flour taste.
  5. Deglaze with white wine (if using), scraping up any brown bits from the bottom of the pot.
  6. Add broth, thyme, rosemary, bay leaf, salt, and pepper. Bring to a simmer and cook for 15–20 minutes to blend flavors. Remove bay leaf.
  7. Preheat broiler. Ladle soup into oven-safe bowls.
  8. Top each bowl with a slice of croissant and sprinkle with shredded cheese.
  9. Place under broiler until cheese is melted and bubbly, 2–4 minutes.
  10. Serve hot, optionally garnished with fresh herbs like parsley or chives.

Notes

  • Add a splash of balsamic vinegar for deeper flavor.
  • Use all vegetable broth for a vegetarian version.
  • Mix gruyère with mozzarella for a more melty cheese topping.
  • Store soup and topping separately to keep croissant from getting soggy.
  • Freeze soup base (without topping) for up to 3 months.

Nutrition

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