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
Preparation
Melt butter in heavy, large saucepan over medium heat.
Add onions, garlic, bay leaf and thyme sprig and sauté 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.
