The Sicilians called this food "maccheroni" as it was made up of a ground nut and maccheroni referred to any food, savory or sweet, made from something ground up - nut, wheat, whatever.
Over time, the sweet maccheroni evolved to incorporate egg whites for leavening and utilized the bitter almonds known so well throughout the Italian peninsula.
This cookie, made from ground almonds, sweetened with sugar, and leavened with egg whites, is more or less what we still know today as the Italian macaroon (the Italians know it as "amaretti" as maccheroni no longer refers to quite as broad an array of foods as it once did)."