Peel, wash, and cut potatoes into large chunks Throw potatoes into a large pot and cover with just enough water to cover the potatoes. Bring potatoes to a boil; reduce heat to medium-high and boil for 25 minutes.
When potatoes are done boiling; drain and add 2 tbsp of sour cream, 4 oz of cream cheese, and 6 tbsp of butter. Cover potatoes with a lid and allow potatoes to steam and the ingredients to melt (about 2 min.)
Remove the lid and mix potatoes with a hand mixer directly in the pot. Mix until you see no more chunks, you may need to use a spatula to scrape the sides and bottom as there can be chunks hiding in some places.
When potatoes are whipped thoroughly with a hand mixer you may add the liquid.
First, add milk (preferably warm) and mix until incorporated then add the half and half. Whip thoroughly until liquid is incorporated in the potatoes.