Chicken Casserole

Ingredients:

• 4 boneless, skinless chicken breasts (cut into bite-sized pieces)
• 2 tablespoons olive oil
• 1 large onion, chopped
• 3 garlic cloves, minced
• 2 carrots, sliced
• 2 celery stalks, sliced
• 1 cup mushrooms, sliced
• 1 cup peas (fresh or frozen)
• 2 cups chicken broth
• 1 cup heavy cream
• 1 cup shredded cheddar cheese
• 1 teaspoon dried thyme
• 1 teaspoon dried rosemary
• Salt and pepper to taste
• 1 cup breadcrumbs
• 2 tablespoons butter,