Halve and then cut onions into thin slices. In a large skillet over medium high heat add olive oil and butter. When the butter is melted add the onions. Cover and cook for about 8 minutes until the ovens are very soft. While the onions are cooking whisk together Worcestershire sauce and flour. Set aside. When the onions are done add to the slow cooker followed by minced garlic and the beef broth. Whisk in the flour and Worcestershire sauce. Salt and Pepper to taste. Cook on low for 7-8 hours.

When the soup is done. Preheat oven to 425 degrees. Ladle soup into a oven safe bowl. Top with a slice or two of toasted baguette and your choice of cheese. Place bowls onto a sturdy sheet pan and place in oven for 8-10 minutes until the cheese is melted and slightly golden brown.

Caution: Bowls will be very hot coming out of the oven. Take care to use a oven mitt and let cool slightly before handling.