Nectarines are a variety of peaches. They are the smooth-skinned peach of the family. A nectarine's skin is a little thinner, and therefore better for crisp or tarts. The nectarine is smaller than a peach; it is about the size of a plump plum. Nectarines are best used for pies, tarts, cobblers, compotes, fruit salads, or in your breakfast cereal.