Place the peeled potato chunks in a large pot, add 1 teaspoon of the salt, and cover them with cold water before setting the pot over the heat. Starting in cold water is key because the potatoes cook evenly from edge to center instead of turning soft outside while the middle stays firm.

Bring the pot to a boil, then reduce the heat and simmer for 12 to 15 minutes. The potatoes are ready when a paring knife slips in and the piece slides off easily with almost no resistance.

While the potatoes cook, warm the butter and milk together until the butter melts completely. The mixture should be hot but not boiling, which helps it blend in quickly without cooling the potatoes down.

Drain the potatoes in a colander, return them to the warm pot, and mash until the large lumps are gone. The potatoes should look steamy and fairly dry at this stage, which sets you up for a lighter texture.

Pour in the warm milk and butter mixture, then fold in the Greek yogurt, garlic powder, and remaining salt, adding pepper to taste if you like. Stir gently until the mash looks smooth and fluffy, then use a spatula for a final soft fold to polish the texture.

Top with chopped fresh chives or parsley and serve while warm. The herbs add a fresh pop against the rich, buttery potatoes.

Cool any leftovers, then transfer them to an airtight container and refrigerate for 3 to 4 days. The texture will firm up as they chill, but it loosens again nicely with gentle reheating and warm dairy.