Combine the onion, vinegar olive oil and capers together in a jar. Boil the potatoes until cooked (10 - 15 minutes).
Drain the potatoes thoroughly. Toss the dressing and parsley leaves over the potatoes, and serve.
Note: All onions belong to the allium family and are known to possess properties which prevent tumours in the stomach, liver and colon.
Makes 6 servings