Wash and scrub the potatoes. Cut in to 1 inch pieces, placing them in a large stock pot. Top with water, and cook until fork tender, about 20 minutes.
Drain potatoes, and return to stock pot. Using a potato masher, butter cutter, or fork, mash the potatoes until very smooth. If you like your mashed potatoes to have a little more texture, feel free to mash less!
Mix in Greek yogurt, 1 tablespoon of olive oil, salt, pepper, and garlic powder. Mix thoroughly to combine. Adjust salt and pepper to your liking. If potatoes are too thick, increase amount of greek yogurt, or loosen them up even further with a splash of milk.
Transfer to a serving bowl, dragging a spoon in a circular motion on top of the potatoes (this should leave a little moat for your olive oil). Drizzle remaining tablespoon in the crevices, and top with salt and pepper.