Peel, boil and drain potatoes. Add in a large bowl, 1/2 stick of butter and mash by hand until butter is melted. Add sour cream and cream cheese, beat well until smooth. Add 2 cups of the cheese, mix well.
Place in a large cake pan or baking dish. Sprinkle with rest of cheese, bacon bits and dollop butter in spots.
Bake at 350 until top is bubbly and everything is melted. Corners should be crisp looking.