Put the potatoes in a medium pot, cover with cold water and add 2 tablespoons salt. Bring to a low simmer and cook the potatoes, uncovered, until tender, about 45 minutes. Drain.
Peel the potatoes and return them to the pot (for smoother potatoes, pass them through a ricer or food mill after peeling). Mash the potatoes with the yogurt and butter using a fork or potato masher. Stir in most of the chives, dill, parsley, 2 teaspoons salt and a few grinds of pepper. Transfer to a serving dish and sprinkle with the reserved herbs.
Copyright 2016 Television Food Network, G.P. All rights reserved.