Place the potatoes into a large pot, and cover with salted water. Bring to a boil, reduce heat to medium-low, cover, and simmer until tender, 20 to 25 minutes. Drain, and return the potatoes to the pot. Turn heat to high, and allow the potatoes to dry for about 30 seconds. Turn off the heat.

Add the cream cheese, sour cream and 6 Tbsp of the butter to the potatoes. Mash the potatoes with a potato masher (or an electric mixer if your arm gets tired!). Keep mashing until completely smooth.

Place the potatoes in a large baking dish (9X13 or something similarly sized). Slice the remaining 2 Tbsp butter very thinly and place the slices evenly over the top of the potatoes. Bake in oven at 300° for about 30 minutes. (If you don’t have time for this step, you can just add the last 2 Tbsp of the butter into the potatoes and serve right after mashing.)