Scrub potatoes under running water. Cut into fourths, cover with cold, salted water. Bring potatoes to a boil and simmer until tender, but not falling apart, about 30 minutes. Drain thoroughly.
Meanwhile, warm cream, garlic and herb leaves together in small saucepan. Mash warm potatoes together with scallions by hand, using a hand masher. Don't try to get potatoes perfectly smooth, they rustic! Strain warm cream and add to potatoes a little at a time, while continuing to mash. Stir in warm, melted butter. Season to taste with salt and pepper.
These work perfectly when made ahead and kept warm on LOW in a GREASED crockpot.