Peel and dice potatoes and add to a large pot. Cover with water and salt the water. Bring to boil over medium heat, and cook until tender. Drain the potatoes and return to hot pot to dry. Transfer potatoes to a bowl. Soften cream cheese in a microwavable bowl and microwave the cream cheese for 20 seconds on high. Add to the potatoes along with sour cream, scallions, zest, egg, salt and pepper, to taste. Mash potatoes to combine mixture.
Heat the oil and butter in nonstick skillet over medium heat. Drop 2-inch mounds of potatoes into skillet and gently press down to flatten a bit. Crisp potatoes until deeply golden on each side, about 7 to 8 minutes total. Mixture makes 8 golden cakes.