Begin by washing your potatoes, then peeling them and chopping into halves or quarters.
If you prefer to leave the skin on, that is fine.
Bring a large pot of salted water to a boil, then add the prepared potatoes, making sure the water covers all of them.
Boil for 10-20 minutes, until the potatoes can be easily poked with a fork.
Use a large fork or slotted spoon to remove the cooked potatoes directly from the water into a large bowl.
Drain any smaller pieces over a colander and (optional) reserve some of the starchy potato water to smooth out the mash later.
If you have a potato ricer, I highly recommend it for the smoothest possible mashed potatoes. If not, just use a potato masher to mash in the bowl to your liking.
After mashing to your liking (but be sure not to over-mash), add the cream cheese, truffle sauce (or other product), and butter.
Continue to stir or mash these together until fully combined, slowly incorporating potato water OR milk (or cream or non-dairy milk) to thin as necessary.
Season with salt and pepper to taste.
Serve hot and drizzle with truffle oil on the top. Optionally, garnish with parsley or chives.