1. Peel the potatoes, and cut them into chunks. Place the potatoes in a 4-quart pot, and add water just to cover. Bring the potatoes to a boil over high heat. Reduce the heat to medium, cover, and cook for 10 minutes, or until the potatoes are soft.
2. Drain all but about 2/3 cup of water from the pot, reserving the drained water. Add the dry milk powder, butter-flavored sprinkles, and pepper to the potatoes, and mash them with a potato masher until smooth. If the potatoes are too stiff, add a little of the reserved cooking liquid.