Preheat oven to 220°C. Line a large baking tray with non-stick baking paper. Place the potato on the prepared tray. Drizzle over half the oil. Bake for 45 minutes or until tender and golden. Transfer to a large bowl.
Meanwhile, combine the olives, parsley, lemon juice, vinegar, capers and remaining oil in a small jug.
Add two-thirds of the olive mixture to the potatoes. Toss to combine. Transfer to a serving platter. Drizzle over the remaining olive mixture.