In a large stockpot, brown the butter.
Add onions and cook over medium/high heat for 30 minutes or until beginning to caramelize.
Add in the beef broth, merlot, Worcestershire sauce, and vinegar.
Bundle up bay leaves, thyme, and parsley and add to soup.
Bring to a boil, then turn down heat and allow to simmer for 30 minutes.
Preheat oven to 425 degrees F.
Cut off the tops of the rolls, then using a spoon or your hands, push down the center of the bread into the bottom of the roll, making a bowl shape.
Bake bread bowls for 7-10 minutes.
Separate cheese between all eight bread bowls and press into bottom, then bake for an additional 4 minutes.
Fill bowls with soup, top with gruyere slices, then sprinkle paprika on top.
Place under high broiler for 2-3 minutes or until cheese is bubbling.
Serve and enjoy!