Dice the potatoes (I like mine with the skins on). Place potatoes in a large sauce pan, add salt and cover with water. Bring to a boil over medium-high heat and cook until potatoes fall apart when poked with a fork (around 20 minutes).
Remove the potatoes from heat and drain the water. Mash the potatoes and add the garlic and milk and whip it together using an electric mixer or whisk. (You could also use a potato masher if you like). Add the Parmesan and mix in with a spoon. Let stand for a few minutes to thicken, then serve.