Creamy Mashed Potatoes - 5 WW points

Place potatoes in a medium pot with enough salted water to cover by 1 inch. Cover and bring to a boil over medium-high heat. Cook until tender, 12-15 minutes. Scoop out and reserve ¼ cup cooking water, then drain. Return empty pot to stove over low heat and add 1 TBSP butter. Once melted, return potatoes to pot; mash until smooth. Stir in cream cheese and sour cream. Add enough cooking water to create a creamy consistency (you may not use all). Season with plenty of salt and pepper. Garnish with chopped scallions, if desired.