Preheat oven to 350°F (175°C). Spray a 9x13-inch baking dish generously with cooking spray.
In a large mixing bowl, combine softened cream cheese and butter. Use a wooden spoon or spatula to mix until smooth and well blended.
Add cream of chicken soup, chicken broth, Italian dressing mix, and minced garlic to the cream cheese mixture. Stir until completely smooth and creamy.
Add cooked shredded chicken and cooked rice to the bowl. Stir until everything is evenly coated with the creamy sauce.
Fold in 1 cup of shredded cheddar cheese. Season with salt and black pepper, then mix well.
Transfer the chicken and rice mixture to the prepared baking dish, spreading it evenly.
Cover the dish tightly with aluminum foil.
Bake covered for 30 minutes.
Remove foil and sprinkle the remaining 1/2 cup of cheddar cheese over the top (and optional breadcrumb topping if using).
Return to oven uncovered and bake for an additional 10 minutes, until cheese is melted and bubbly and the top is golden.
Remove from oven and let rest for 5 minutes.
Garnish with fresh chopped parsley before serving.