Pressure cook the potatoes till really soft and done. Peel and place into a bowl.
Using a potato masher, mash till smooth.
Add the soft butter and milk, along with the seasonings and continue to whip with the masher till the mixture becomes really smooth.
Mix in the parsley.
Allow it to rest for sometime, then enjoy as side to steak and vegetables.
Notes
Use potatoes which are floury in nature so that you don't have any lumps once the mixture is beaten. Add upto 100 gm butter if you like your potatoes to be really rich.