Place the potatoes into a large pot, cover with water and boil until tender (but not falling apart) then drain and return to the same pot (but with the heat off).
1 kg mashing potatoes
Using a potato ricer or masher, mash the potatoes until smooth.
Add in salted butter, sour cream, parmesan cheese, and garlic powder and mix to combine.
80 g salted butter, 65 g sour cream, 15 g parmesan cheese, ½ teaspoon garlic powder
Turn the heat back on to low, and gradually mix in milk until you achieve the desired consistency and mash is warmed through.
2-3 tablespoon milk
Gradually mix in truffle oil and salt and pepper to taste then serve.
1 teaspoon truffle oil, salt and pepper