French Onion Soup Gratinee - PB on Life

Ingredients

• 2 tablespoons unsalted butter
• 5 medium red onions (about 3 pounds), sliced thin
• Table salt
• 6 cups low-sodium chicken broth (canned)
• 1 ¾ cups low-sodium beef broth (canned)
• ¼ cup dry red wine
• 2 sprigs fresh parsley leaves
• 1 sprig fresh thyme
• 1 bay leaf
• 1 tablespoon balsamic vinegar
• Ground black pepper
• 1 baguette, cut on the bias into 3/4-inch slices (2 slices per serving)
• 4 ½ ounces Swiss cheese, sliced 1/16-inch thick
• 1 ½ ounces grated Asiago cheese (about 3/4 cup)