Savory French Onion Meatloaf with Cheese Sauce - Graceful Flavors

Ingredients

• 2 lbs ground beef (80/20 blend)
• 2 large eggs
• 1 cup Panko breadcrumbs
• 2 tablespoons Worcestershire sauce
• 2 teaspoons Dijon mustard
• 1 tablespoon fresh thyme, chopped
• 1 ½ teaspoons salt
• 1 teaspoon ground black pepper
• 3 large sweet onions, thinly sliced
• 2 tablespoons olive oil
• 4 cloves garlic, minced
• 1 cup beef broth
• ½ cup milk
• 1 cup Mozzarella cheese, shredded
• 1 cup Gruyère cheese, shredded
• 2 tablespoons butter
• 1 tablespoon all-purpose flour