Peal the potatoes and cut them into small cubes, about 1/2 inch. Put them in a 3 quart pot and add water to cover them 2 inches. Bring the water to a boil and cook until a fork can easily slide through the potatoes, about 15-20 minutes.
Drain the water and place the potatoes in a bowl.
Add all the other ingredients - milk, mayonnaise, butter, salt, garlic powder, parsley and pepper. Using a potato smasher, hand blender, or stand up mixer, thoroughly mix all the ingredients until the potatoes as creamy.