1use a vegetable peeler and remove the skins from the turnips, dice and place in a large pot. (some turnips come with a waxy coating that will come off when peeled).
2place the potato in with turnips (do not peel). this will get rid of the bitter taste of the turnips while they are cooking.
3cover the turnips with cool water and place on the stove. add salt and bring to a boil. reduce heat to medium and cover. cook for about 15 minutes or until turnips are tender when pierced with a fork.
4while the turnips are cooking, drain and remove potato. pour turnips back into pot and mash with potato masher. stir in the garlic milk mixture a little at a time, then stirring in remaining butter.
5you may not need all of the milk. gently stir and add in the parmesan. serve warm.