French Onion Soup in the Crock Pot

Our 'cousin' Nancy Shullick Danese contributed this surprisingly easy-to-put-together recipe.  Nancy told me that this is a family favorite, particularly for her husband, Mario. They enjoyed it with steaks on the grill and a tossed salad for their 25th anniversary last year.
Ingredients
3 Tablespoons butter
4-6 cups of sweet onion, sliced thin
1 Tablespoon flour
5 cups beef stock or water
1 Tablespoon Worcestshire sauce
¼ cup white wine
Thick slices of French bread
1 ½ cups shredded mozzarella cheese
   or provolone cheese
Fresh thyme for garnish (optional)
Method
In a large saute pan, melt 2-3 tablespoons butter over low heat. Add the 4-6 cups of sliced sweet onions. Cover and cook for 15-20 minutes on the stovetop, or until onions are soft. Do not burn!
While onions are cooking, turn on crock pot. In the crock pot, mix 1 tablespoon flour, 5 cups water or beef stock, 1 tablespoon Worcestershire sauce, salt and pepper to your taste, and ¼ cup white wine. Simmer altogether.  Add the onions to the contents of the stock pot, once they are cooked soft.  Simmer for 2-3 hours.
To serve: Ladle soup into individual serving mini-crocks. Place one thick slice of French bread on top of soup. Cover each with mozzarella and/or provolone cheese.Place under broiler until cheese melts and is golden brown in color. Garnish with fresh thyme and serve with more crusty bread.
French Onion Soup Printable Version