Bring the potatoes to a boil on high heat and reduce to a simmer. Cook them for about 20-30 minutes until they are tender but not falling apart
Meanwhile combine the milk and the butter in a small pot, add a pinch of salt and heat on a low flame.
Strain the cooked potatoes into a colander. Press or turn them in a potato masher or mouli into a pot.
Add the warm milk and butter mixture to the potatoes and stir well with a wooden spoon.
To make the mash extra creamy and lump free, pass them through a sieve (mesh strainer) using a firm spatula.