Ingredients:

  • 4 large Yellow Onions (thinly sliced)
  • 4 Tbsp Unsalted Butter
  • 2 Tbsp Olive Oil
  • 4 Fresh Thyme Sprigs
  • 1 tsp Fresh Rosemary (finely chopped)
  • 3 Tbsp All-Purpose Flour
  • 1/2 cup Dry Sherry or Dry White Wine
  • 6 cups Beef or Mushroom Broth (low sodium)
  • 8 oz Mixed Mushrooms (Cremini, Shiitake, roughly chopped)
  • 1/2 cup Heavy Cream (35% fat)
  • 1 tsp Dijon Mustard
  • Kosher Salt (to taste)
  • Freshly Ground Black Pepper (to taste)
  • 1 small Baguette (sliced 1-inch thick)
  • 1 clove Garlic (halved, for rubbing, optional)
  • 6 oz Gruyère Cheese (freshly grated)

Instructions:

  1. Melt butter and oil in a large, heavy-bottomed Dutch oven over medium-low heat. Add onions, salt, rosemary, and thyme. Stir frequently for the first 20 minutes, then reduce heat to low. Cook very slowly for 1 hour to 1 hour 15 minutes, until deeply mahogany brown and sweet.
  2. While onions are cooking during the last 15 minutes, sauté the chopped mushrooms in a separate pan with a knob of butter until nicely browned. Set aside.
  3. Once onions are perfectly caramelised, stir in the flour and cook for 2 minutes (creating a roux). Pour in the sherry/wine, scraping up any browned bits (the fond) from the bottom of the pot. Cook until reduced by half.
  4. Add the broth and Dijon mustard. Bring to a gentle simmer, cover partially, and cook for 20 minutes to allow flavours to meld.
  5. Remove and discard the thyme sprigs. Stir in the sautéed mushrooms and heavy cream. Heat through gently—do not boil once the cream is added. Taste and adjust salt and pepper.
  6. Preheat the broiler. Rub toasted baguette slices lightly with cut garlic, if desired. Ladle the Creamy French Onion and Mushroom Soup into oven-safe bowls. Top each bowl with 2-3 slices of bread.
  7. Generously cover the bread with grated Gruyère cheese. Place bowls on a baking sheet and broil for 2–4 minutes, watching carefully, until the cheese is bubbly, golden, and slightly browned.