French Onion Soup

I had beef soup bones from Burns Angus Farm in my freezer and I wanted to make soup while it was still cold outside.  I made beef stock, a smaller version of this recipe, with the soup bones, celery, onions, carrots, garlic, bay leaves and water.  Then I made a fabulous French onion soup:

French Onion Soup
4 Servings
Active Time: 30 min
Total Time: 1 1/2 hours

1 pound onions, cut in half and sliced thinly lengthwise
2 tablespoons oil (I used half butter half olive oil)
2 tablespoons flour
1/2 cup port wine
8 cups beef stock
1 bay leaf
1 tablespoon dried thyme
Salt and pepper to taste
4 pieces of crusty bread, cut into 1 1/2 inch thick slices
1/2 pound gruyere cheese, sliced thinly or grated
4 ovensafe bowls

Heat oil in a stockpot on medium-low then add onions.  Cook onions on medium-low heat, stirring occasionally, until brown and caramelized (45 minutes - 1 hour).  Stir in flour then add port wine and continue stirring until thickened, about 2 minutes.  Next add beef stock, bay leaf, and thyme and turn up heat to medium high until boiling.  Once boiling, turn down the heat and simmer for about 20 minutes so flavors can meld.  During that time, toast the bread under the broiler on low until golden brown, about 3-4 minutes per side.  Remove bay leaf from soup and add desired quantity of salt and pepper, then pour into oven safe bowls.  Float a slice of bread onto each bowl of soup and top with gruyere cheese.  Put the bowls in the oven and broil on low until cheese is melted and bubbly, about 6 minutes.  Serve immediately.