Peel and dice potatoes. Place in a medium pan, add the salt, and cover with water.
Bring to a boil over medium-high heat and then reduce heat to medium. Cook until potatoes are tender.
Heat the milk in a pot over medium heat until simmering. Remove from heat and set aside.
Remove the potatoes from the heat and drain off the water. Mash the potatoes and add the milk, butter, egg yolks and cheese & stir to combine. Sprinkle with ground cumin and scallions. Serve warm.