French Onion Soup | Bookbinder's Recipes

Ingredients

• 3 tbsp butter
• 2 ½ pounds yellow onions, thinly sliced
• 1 tbsp flour
• Salt and pepper to taste
• 4 cups beef broth
• 1 tbsp Bookbinder's Stone Ground Dijon Mustard
• ½ tsp thyme
• ½ cup cubed bread
• 2 cups shredded gruyere