From AB, seems to be well-reviewed.
Ingredients
3 1/2 pounds russet potatoes
2 tablespoons kosher salt
16 fl oz (2 cups) half-and-half
6 cloves garlic, crushed
6 oz grated Parmesan
Instructions
Peel and dice potatoes, making sure all are relatively the same size (he dices the potatoes into fairly small pieces and puts them in a pot of water to soak for 30 minutes, then drains). Place in a large saucepan, add the salt, and cover with water. Bring to a boil over medium-high heat and then reduce heat to maintain a rolling boil (in the video it looked like a very low simmer). Cook until potatoes fall apart when poked with a fork (30 minutes for him, he squeezed a piece with tongs).
Heat the half-and-half and the garlic in a medium saucepan over medium heat until simmering (in the video he says "gurgle for 10 minutes then kill the heat"). Remove from heat and set aside.
Remove the potatoes from the heat and drain off the water. Mash and add the garlic-cream mixture and Parmesan; stir to combine. (In the video, he adds the garlic-cream to the potatoes before they're mashed and then mashes the whole bunch using the old-style potato masher, then adds parmesan.) Let stand for 5 minutes so that mixture thickens and then serve.