Peel and cut potatoes into cubes, boil until tender and drain. Put in a 9x13-inch pan.
Cut butter into cubes and place along the potatoes and season with salt and pepper. Put sour cream on the potatoes and spread across. Cut Velveeta Cheese into 9 blocks and place on top of the potato mixture.
Bake at 350°F for 30 minutes. Stir mixture occasionally.