Plum tomatoes are best for sauces because they produce a sauce with more pulp and less juice, but any full-flavored vine-ripened tomato may be used as long as the excess juice is quickly reduced. Extra-virgin olive oil is not usually used for sautéing because the flavor dissipates when exposed to heat. But this sauce is cooked so quickly that the fruitiness of the oil gives an added dimension to the olives.