French Onion Soup

I had French Onion soup in an airport during a layover earlier this year, and ever since then I've wanted to make some myself.  Of course, summer isn't really the time of year for eating hot, cozy soup with melty cheesy bread, so I waited until fall to try out this recipe.  There are tons of recipes for French Onion soup, and I think I'm going to search around for some different ones, but this is a nice basic one for the crock pot.  We had some for dinner and then I froze the rest so we can have it all through the fall!

(recipe adapted from Betty Crocker's Slow Cooker Cookbook)
INGREDIENTS:
3 large onions, sliced (appx 3 cups) 3 tbsp butter, melted 3 tbsp all purpose flour 1 tbsp Worcestershire sauce 1 tsp sugar 1/4 tsp pepper 4 14.5oz cans beef broth Sliced French Bread Shredded Mozzarella cheese (and some parmesan if you have it!)
1. Mix the onions and butter in a 3 1/3 to 6 quart slow cooker,  cover and cook on high for about 30-40 minutes, until the onions begin to slightly brown around the edges.
2. In a small bowl, mix the flour, Worcestershire sauce, sugar, and pepper.  Then, stir the mixture along with your beef broth into the slowcooker full of onions.  Cover again and cook it on low for 7-9 hours, (or on high for 3-4 hours), or just until the onions are tender.
3. Cut some slices of french bread, put some grated mozzarella on top and stick it in the oven on broil for a few minutes, until the cheese is all gooey and melty.  I also threw some shredded cheese in the bottom of the bowl before ladling the soup in, so there'd be a cheesy surprise at the bottom.  Put one of your cheesy breads on top of each bowl of soup, and consume!