Preheat the oven to 400 F.
Peel potatoes, if desired, then quarter lengthways. Place cut potatoes in a large saucepan or stockpot filled with salted cold water. Bring to a boil, then lower the heat and simmer for about 8 minutes.
Drain the potatoes in a colander and sprinkle with the turmeric, chili flakes and some salt and pepper. Toss potatoes gently in the colander to coat evenly, then drizzle with a little olive oil and toss again. Let rest in the colander for 5 minutes.
Pour the remaining olive oil in a shallow roasting tray or jelly roll pan. Place tray in the oven for a few minutes to heat up. Carefully add the potatoes and toss to coat in the oil. Roast for 40 to 45 minutes, turning a few times, until potatoes are crisp and golden. Drain potatoes on paper towels. To serve, transfer potatoes to a warmed bowl or platter.