To cook the potatoes
Cook the potatoes (uncovered) in salted water over a medium heat for approx. 20 mins. until very soft. Drain the water, allow the residual moisture on the potatoes to evaporate by shaking the pan on the switched-off hob. Press the potatoes through a food mill or mash them with a potato masher.
To prepare the mash
Gradually add the milk and butter to the potatoes, stirring with a wooden spoon. Return the pan to the warm hob a few times if necessary. Stir briefly and vigorously until the potato mixture is fluffy and falls off the spoon, season.