Cut the potatoes into 1-inch cubes and place them in a large pot. Add enough water to cover the potatoes and add salt. Bring to a boil, then lower the heat and simmer, uncovered, for 15-20 minutes, until the potatoes fall apart easily when pierced with a fork.
Meanwhile,heat the milk and butter in a small saucepan, until the butter is melted. Keep warm.
As soon as the potatoes are tender, drain them in a colander.
Place hot potatoes in mixing bowl and mix until smooth, about 1 minute.
Slowly add in milk/butter mixture.
Turn up speed and beat for about 30 seconds, or until milk is absorbed.
Serve warm topped with extra butter and parsley (if desired).