Preheat your oven to 375 degrees. Prepare a 9x13 casserole dish with nonstick cooking spray.
Wash, peel, dice, potatoes and place them in a large pot. Cover with water and boil until potatoes are tender.
Drain your potatoes and gently place them back into your now empty pot. Gently fold on butter, cream cheese, sour cream, and milk.
Last gently add in garlic powder, salt, and pepper along with 1 ½ cups shredded cheese and 1 cup bacon. Pour this into your prepared casserole dish.
Top your potatoes with the remaining cheese and bacon. Bake for 25-30 minutes.
Remove your casserole from the oven and top with green onions and serve.
