Salt a large pot of cold water with 3 tablespoons salt. Add the chopped potatoes, cover and boil over high heat. Once the water reaches a boil, lower heat to medium and cook for 15 minutes or until the potatoes are fork tender. Drain the potatoes well and return to the pot. Add the cream cheese, butter, and buttermilk and use an electric mixer to mix till mostly creamy. I think these potatoes are better with a bit of chunks in them. Taste and see if they need any more salt before adding the salt. Sometimes the salt in the water will lend to the potatoes being perfectly salted.