In doing so, I typically will utilize a 1/2" thick chuck steak in making this version; for not only is it an economical cut of steak with lots of flavor, but after 6 or 7 hours in the slow cooker it turns out to be as tender as most finer cuts of beef. I also present it here with one of my favorite cheeses - Muenster; a nice alternative to the more commonly used Gruyere or Mozzarella. I've even used sliced Fontina topped with a sprinkle of grated Asiago. Your only limitation is your imagination!
1. Over medium-high heat, melt butter in a large skillet. Add onions and cook until they soften and become transluscent; about 8 to 10 minutes.
2. When soft, add garlic and stir another minute or so until fragrant. Lower heat to medium and add brown sugar and Worcestershire sauce and cook another 10 minutes, stirring frequently. De-glaze pan with sherry.
3. Pour onions into beef broth in a slow cooker. Add salt, pepper, thyme, bay leaf, and beef cubes. Set on low and let cook 6-8 hours.
4. When ready, place 1/2" slices of French bread beneath broiler about a minute per side. Pour soup in crock, top with toasted French bread and a slice or two of Muenster or Gruyere cheese. Place crock beneath broiler for a minute or two, until cheese is slightly browned and bubbling.