Place the potato chunks into a large saucepan. Fill the saucepan with enough water to cover the potatoes. Bring to a boil and cook until fork tender, about 15 minutes. Meanwhile, warm the heavy cream over medium-low heat in a small saucepan. Transfer to a large bowl. Drain the potatoes. Using a potato ricer, rice the potatoes directly into the warm cream. Using a whisk or wooden spoon, stir until the potatoes are smooth. Begin adding the butter and stir to incorporate. Season with salt and pepper. Transfer to a serving vessel and drizzle with a little oil. Sprinkle the dish with minced chives if desired.