Classic French Onion Soup

You know it.  You love it.
Molten hot soup with caramelized onions in a rich, beef broth covered with lots of melted cheese that comes up right up in strings with the first spoonful.
This is an easy version that might not be the French recipe the Julia Child would make, but it serves 2-3 people if you want to serve it as a soup course. You can certainly make your own beef broth - My recipe for Homemade Savory Beef Broth - but in the warmer months, it's easier to use a good store bought broth. I prefer to top mine with some Parmesan and Mozzarella.

4 Tbsp. unsalted butter 2 lbs. sweet onions (2 large) halved and sliced thin Salt and Pepper 1 Tbsp. packed brown sugar 1 tsp. minced fresh thyme 3/4 cup dry red wine 2 cups beef broth 2 cups chicken broth 2-3 heaping Tbsp. flour 1/4 cup soy sauce 1 small baguette, cut into 1/2-inch slices Shredded cheese of your choice (Swiss, Provolone, Mozzarella) Parmesan cheese
Add butter to stock pot and cook until melted.  Add onions,  2 tsp. salt, 1 tsp. pepper, brown sugar and thyme.  Cook onions over medium heat until onions are softened and deep golden brown (20-30 minutes.
Add stock and bring to a simmer.  Simmer gently for 20-30 minutes.  Mix flour and soy sauce to form a slurry.  Whisk in to soup and whisk until smooth.  Cook an additional 5 minutes.
Preheat oven to 400 degrees F.  Arrange bread slices in single layer on baking sheet and bake until bread is golden at edges, about 10 minutes. Turn oven to BROIL.
Divide toasted bread into soup bowls or crocks.  Top with a sprinkling of parmesan cheese. Ladle hot soup into bowl until full.  Top with plenty of mozzarella (or cheese of your choice), and broil until cheese is melted and lightly browned.