1lbyellow onions,peeled and sliced (approx. 3 large onions)
3/4cupdry white wine
Kosher salt and freshly ground pepperto taste
10 -12slicesof crusty baguette bread(optional)
In a large pot, melt butter over medium heat. Add the onions, stir well, cover and cook for 5 minutes. Uncover the pot, reduce heat to medium-low and continue to sauté, stirring occasionally, until onions are tender and golden brown, about 25 -30 minutes.
Increase heat to medium-high. Sprinkle the flour over the onions and stir until combined. Add the wine, beef broth, thyme, bay leaf and Worcestershire sauce. Taste and add more salt and/or pepper if you like. At first boil, reduce heat to medium-low and simmer, uncovered about 30 minutes. Taste and adjust the seasoning if necessary. Remove bay leaf and discard.
Place rack of your oven in the center and turn the broil on.
Distributed the soup into individual bowls, place 1-2 slices of bread over the soup and sprinkle with plenty of Gruyere cheese.
Bake until cheese is melted and bubbling, about 2-3 minutes.
If you want you can toast the bread before you put in the soup to give a crisper consistency.