While the potatoes cook, add heavy cream, butter, and smashed garlic cloves to a pan. Bring to a simmer and heat for 10 minutes. Discard garlic cloves, then set aside until needed.

Drain potatoes, then transfer to a ricer or foley mill. Place the foley mill over a bowl, then turn the handle to press the potatoes through. Repeat until all potatoes are riced.

To the bowl of potatoes, add warmed heavy cream and butter, sour cream, chives, salt, and pepper. Stir to combine. Serve with additional chives on top. Enjoy immediately!