This such a simple dish with so much flavor. Just tossed with fresh rosemary, olive oil and roasted. The fingerlings are creamy and tender, but small new or red potatoes would be a good substitute. I prefer kalamata olives, but use your favorite. For this dish, I really prefer grape or cherry tomatoes vs plum or Roma tomatoes. This is a very forgiving dish, there is no right or wrong, you can add more tomatoes, potatoes or olives according to your specific tastes. Serve with roasted chicken or lamb are my favorites, but it really is a wonderful easy side dish.