Ingredients
4 tablespoons butter
1 teaspoon salt
2 large red onions, thinly sliced
2 large sweet onions, thinly sliced
1 (48 fluid ounce) can chicken broth
1 (14 ounce) can beef broth
1/2 cup red wine
1 tablespoon Worcestershire sauce
2 sprigs fresh parsley
1 sprig fresh thyme leaves
1 bay leaf
1 tablespoon balsamic vinegar
salt and freshly ground black pepper to taste
4 thick slices French or Italian bread
8 slices Gruyere or Swiss cheese slices, room temperature
1/2 cup shredded Asiago or mozzarella cheese, room temperature
4 pinches paprika
Preparation
