Preheat oven 350 degrees. Spray a large baking dish with cooking spray and set aside.
Peel potatoes and chop into large, evenly sized pieces. Boil potatoes for 15-20 minutes or until soft when pierced with a fork. Drain the potatoes and beat with a mixer until smooth. Add milk, cream cheese, sour cream, parsley, garlic salt, and pepper. Beat at at low speed until nice and creamy.
Spoon the potatoes into the prepared baking dish. Top with the shredded cheddar cheese and crumbled bacon. Cover with foil and bake for 30 minutes. Remove foil and bake for 10 more minutes or until cheese melts. Enjoy!