It is always best to boil potatoes in their skins, even if they are to be mashed. Not only does this help to prevent the flesh from absorbing too much cooking water, it also conserves vitamins which are concentrated in or just below the skin. Serve the potatoes whole in their skins or, for mashing, peel them as soon as the cooked potatoes are cool enough to handle.
An alternative, particularly at the end of the season when they tend to absorb more moisture, is to oven-bake the potatoes in their skins and then mash them. This is a common practice commercially. It is always worth making extra mashed potatoes as the leftovers are very good for thickening soups, making potato scones, fish cakes, bubble and squeak or hashes, or for topping fish pies. Alternatively, blend leftover mashed potato into small, hot, and savory cheese puffs.
** Asian Recipes