Ingredients

  • Soup:
  • 1/4 cup butter
  • 6 medium-sized onion, peeled, sliced
  • 6 cloves of garlic, peeled, sliced
  • 1 Bay Leaf
  • 1 sprig fresh thyme
  • 1 tablespoon Dijon mustard
  • 1 1/2 cups dry white wine
  • 3 cups chicken stock
  • 3 cups beef stock
  • coarse salt, and freshly cracked black pepper
  • Topping:
  • 4 slices sourdough bread, toasted
  • 1 cup gruyere cheese, grated
  • 1/2 cup parmesan cheese, grated

Method

  • Melt butter in heavy, large saucepan over medium heat.
  • Add onions, garlic, bay leaf and thyme sprig and saute until very tender and brown, about 25 minutes.
  • Add 1/4 cup wine to deglaze pot every 5 minutes for 20 minutes (total onion cooking time is 45 minutes).
  • Stir in Dijon mustard.
  • Add white wine and simmer until reduced to a syrup consistency, about 3 minutes.
  • Stir in chicken stock and beef stock.
  • Simmer 20 minutes.
  • Season to taste with salt and pepper.
  • Preheat broiler.
  • Ladle soup into ovenproof bowls.
  • Top each with slice of toast and grated cheeses.
  • Broil until cheeses melt and bubble.