Rating: 5 stars
1 Ratings
  • 5 star values: 1
  • 4 star values: 0
  • 3 star values: 0
  • 2 star values: 0
  • 1 star values: 0

Most French onion soup recipes call for beef stock, but substituting mushroom broth instead creates a surprisingly rich soup, full on flavor - without the meat. Could become a staple recipe in vegetarian or meat-loving households! A long cooking time and savory ingredients mean this soup is pretty darn rich. Add in the toasted baguette slices and all that gooey Gruyere... this soup is definitely the main course. Serve alongside a crisp, green salad.


Recipe Summary

20 mins
2 hrs 10 mins
2 hrs 30 mins
4 servings


Original recipe yields 4 servings
The ingredient list now reflects the servings specified
Ingredient Checklist


Instructions Checklist
  • Melt butter and olive oil in a pot over medium heat. Add red onions and sweet onions; sprinkle with kosher salt and sugar. Cook, stirring frequently, until onions are very tender and caramelized, about 45 minutes.

  • Pour mushroom broth, sherry, Worcestershire sauce, parsley, herbes de Provence, and bay leaves into onion mixture. Bring to a simmer and cook over medium-low heat for 45 to 60 minutes.

  • Reduce heat to low and remove bay leaves. Pour balsamic vinegar into soup and adjust seasoning. Mix well.

  • Place Parmesan cheese rind in the center of the pot and submerge, but do not stir. Cook soup for an additional 20 minutes.

  • Set an oven rack about 6 inches from the heat source and preheat the oven's broiler.

  • Arrange bread slices on a baking sheet.

  • Broil bread slices in the preheated oven for 2 to 3 minutes per side. Remove from the oven and set aside.

  • Carefully remove cheese rind from the pot and discard.

  • Fill 4 oven-safe bowls evenly with soup and sprinkle each with a light layer of grated Gruyere cheese and Parmesan cheese. Top each with 2 bread slices and sprinkle each with remaining Gruyere cheese and Parmesan cheese. Place bowls on a baking sheet.

  • Broil soup in the preheated oven until cheese is browned and bubbling, 3 to 5 minutes.

Cook's Notes:

Slice onions as thinly as possible for best presentation and texture. You can use yellow onions instead of sweet, if desired.

Substitute dry white wine for fino dry sherry and dried thyme for herbes de Provence if you don't have them on hand.

Add another 32-ounce carton of mushroom broth if you prefer a thinner, soupier consistency; the recipe as written produces a thick soup.

Nutrition Facts

478 calories; protein 21.1g; carbohydrates 36.5g; fat 25.9g; cholesterol 56.1mg; sodium 1908.2mg. Full Nutrition