Prosciutto is a hindquarter cut of pork that's cured, dried, and age. Thinly sliced, the best ones are ever-so-slightly sweet with just the right degree of saltiness, and a silken texture that melts in your mouth. Traditionally the best prosciutto is from Italy; Prosciutto di Parma, is best eaten plain or wrapped around fruits or vegetables. If the prosciutto is to be cooked—it can make a flavorful addition to soup, stews, pasta sauces, egg dishes—consider using a lesser grade.
Speck is prosciutto that has been smoked.
Thin sliced Jambon from Spain or other hams can make a good substitution, especially in cooked dishes. Just watch for salt content as good prosciutto is not overly salty.
Slicing prosciutto paper thin is practically an art form so buy your prosicutto from a trusted source; an Italian market is a good choice. Until recently most prosciutto made in the United States has been of a far lesser quality; however there are some artisanal makers of it worth checking out.
When cooking with prosciutto, add it at the very last minute to keep it from toughening.
When sliced, prosciutto is layerd between pieces of butcher paper; store it that way, too, in the refrigerator where it will keep for a week or more. Cryovaced prosciutto, unopened, will last longer.