Preheat oven to 350℉/175℃.
In a large pot, cover the potatoes in 6 quarts of cold water, or enough to cover. Bring potatoes to a boil and then reduce the heat to medium-low and cook for 20-30 minutes until potatoes are tender.
Drain off potatoes and transfer them to a sheet tray. Place them in a 350°F/175°C oven to dry for 10-15 minutes.
Mash together the potatoes, butter, cream and salt in a large mixing bowl or the pot that you cooked them in. Mash together until just combined. Try not to overwork the starch.
Press the mashed potatoes through a fine mesh strainer for a silky purée. I typically use a small ladle to push them through.
Adjust with more cream and salt if needed, ensuring potatoes remain slightly loose.