Place the potatoes into a large pot, and fill with enough water to cover. Bring to a boil over medium-high heat, and cook until tender and can be pierced with a fork, about 20 minutes.
Meanwhile, place 1 tablespoon olive oil in a skillet, and heat over medium-high heat. Stir in the onion and cook until translucent and lightly browned, about 6 minutes.
Drain water from the potatoes, and mash. Stir in the onion, and continue mashing. Mix in the turmeric, salt, pepper, and cumin. Add the remaining 2 tablespoons olive oil, or amount desired to make the potatoes more or less creamy.