Scrub potatoes clean. Transfer to a saucepan and cover with cold water by at least 1 inch. Stir in salt until dissolved.

Cover, set over high heat, and bring to a boil. Once boiling, remove the lid and reduce the heat to a simmer. Cook until tender all the way through, about 15 to 20 minutes.

Drain, peel and mash with butter. Add hot milk and season with salt and pepper. Mash until smooth and fluffy.