Ultimate Baked Chicken Divan with Creamy Sherry Sauce

Ingredients

• 1 ½ pounds boneless, skinless chicken breasts
• 4 cups broccoli florets (fresh or frozen)
• Salt and pepper to taste
• 3 tablespoons unsalted butter
• 1 medium onion, finely chopped
• 2 cloves garlic, minced
• ¼ cup all-purpose flour
• 2 cups chicken broth
• 1 cup heavy cream
• ½ cup dry sherry
• 1 teaspoon Dijon mustard
• 1 teaspoon Worcestershire sauce
• 1 cup shredded sharp cheddar cheese (divided)
• ½ cup breadcrumbs
• 2 tablespoons unsalted butter, melted
• ¼ cup grated Parmesan cheese