Peel all the potatoes and dice them into 1-inch cubes. This doesn’t have to be perfect but try your best to get them to be uniform in size.
If you own a steam-basket, great—use it! I don’t own one so I made a make-shift steam basket by filling up a 3-quart Dutch oven/pot with a few inches of water. I then nestled a sieve on top and added the potatoes to it and covered the potatoes with foil.
Place your steam basket/make-shift thing over medium-high heat. Steam the potatoes for about 30 to 35 minutes, stirring them about half way through. Give them a taste and make sure they’re VERY soft. Remove them from the steam basket and run them through the potato ricer, in batches, into the bowl or a stand-up mixer (or just a regular ol’ medium bowl).
Repeat this step until you’ve worked your way through all of the potatoes.
In a small saucepan, add the heavy cream and butter. Warm over medium-low heat until the butter has melted. Pour that into the stand-up mixer bowl, along with the salt and pepper and beat, with the paddle attachment, for about 1 minute. Scrap down the sides, if you need to. Give it a taste and adjust the salt to your liking.
If you don’t own a stand-up mixer, you can do this last part in a medium bowl and mix it using a spatula.