Leftover Thanksgiving Dinner Casserole - Six Sisters' Stuff

Ingredients

• 3 celery stalks (diced)
• 1 onion (diced)
• 2 apples (seeded and diced)
• ⅓ cup butter
• 6 cups cubed seasoned stuffing
• 1 cup chicken broth
• 4 cups turkey (cooked and diced)
• 2 10.75 ounce cream of chicken soup
• 1 teaspoon garlic powder
• ¼ cup sour cream
• 4 cups mashed potatoes (prepared)
• ½ teaspoon pepper
• ¼ teaspoon salt
• 1 ½ cups shredded cheddar cheese