Put peppers (capsicums) under a hot grill, turning them until skins are blistered and black all over. Place in a polythene hag and leave to cool for 10-15 minutes. Peel skins off, remove stems and seeds and cut flesh into strips. Arrange in a shallow dish.
Drizzle olive oil over peppers. Peel garlic, cut into slivers and scatter over peppers. Season with salt and pepper, then leave to marinate for 24 hours.
Serve garnished with black olives and parsley.