Peel the potatoes and then cut into 1 inch chunks.
Wash the potatoes under cold water to remove any surface starch.
Place the potatoes, milk, salt and white pepper into a sauce pan and place over a medium heat.
Bring to a simmer, then put a lid on, reduce the heat and cook for 35-40 minutes until the potatoes are soft. (Check your potatoes after 20 minutes as the age of the potato can affect how quickly it cooks.)
Whilst the potatoes are cooking, cut the butter into small chunks and place in the fridge to stay cold.
Drain the potatoes reserving the milk.
Use a potato ricer or a food mill to mash the potatoes.
Add the hot potatoes to the cold butter and stir vigorously until all the butter has melted into the potato.
Add about a ¼ cup of the milk mixture and stir to get a very soft almost pourable mashed potato. (see note 2)
Check the seasoning then serve immediately with a little extra butter and some parsley garnish.
