At this point, situate a food mill over a large bowl or pot. Add a few potatoes at a time and press through the food mill. Alternately you can use a ricer or, should you want to go old-school, use a hand-held masher. Just be sure that while the potatoes are still warm, add the heated milk the butter, salt and pepper. If you wait until they’ve become cold, the flavors will not meld properly. Taste. Add salt and pepper until it taste good to you.