Boil the peeled and quartered potatoes in salted water until very tender.
While the potatoes are boiling, 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.
Melt 1-2 tablespoons of butter in a deep frying pan and saute the sliced Savoy cabbage over low heat till wilted and tender for about 5 minutes. Alternatively, you can steam the cabbage instead.
Drain the potatoes and steam dry them to get rid of the excess of water. Return them to the pot and add hot milk together with the sliced green onions, start mashing with a potato masher until mostly smooth, then add butter and keep mashing. Stir in the cooked cabbage and season well with salt and pepper.
