Add sliced green onions to milk and bring to a boil at low heat, take off the heat and let the green onions infuse the milk.
Boil the peeled and quartered potatoes in salted water until very tender. Drain the potatoes and let them steam dry for 2-3 minutes, pour in hot milk with the onions and mash well, add butter and salt and white pepper to taste.
Notes
Use starchy or floury potatoes such as Yukon Gold or Russet in the US or Maris Piper, King Edward, Vivaldi and Desiree in the UK.