1. place oil and lemon juice into a screw top jar. season with salt and pepper 2. place top on jar and shake till dressing is combined. 3. wash lettuce and watercress, drain well. tear into small pieces 4. toss dressing through salad greens and arrange on serving platter 5. arrange tomato slices, onion rings and olives in circular pattern 6. sprinkle with chopped parsley before serving. serve immediately.