Peel the potatoes and cut them into large, even chunks. Place them in a bowl, cover with cold water, and rinse briefly to remove some of the excess surface starch. Drain well.
Transfer the rinsed potatoes to a large saucepan. Add the heavy cream, water, salt, and butter, then set the pan over medium heat.
Bring the mixture to a gentle boil, then reduce the heat to low, cover, and simmer for 20 to 25 minutes, or until the potatoes are completely fork-tender.
Pour off any excess cooking liquid, but reserve some in case you need it later. Mash the potatoes while they are still hot until mostly smooth.
Add a little of the reserved creamy cooking liquid while mashing, just until the potatoes reach the smooth, creamy consistency you like.
Stir in 1 tablespoon of cream cheese while the potatoes are still hot. Gently fold until smooth, fluffy, and creamy, then taste and adjust the salt and black pepper as needed.
Season to taste and serve topped with butter and chives.