Both almond flour and almond meal are made from ground almonds, though they have two subtle differences that set them apart. - Almond flour is typically made from blanched almonds, which have had the skins removed, while almond meal still has the skins. - Almond flour is ground more finely than almond meal, which typically has a more coarse grind. For this recipe, I used almond flour. You can also get great results using almond meal (made from whole ground almonds), although the amaretti texture might be a bit rougher.   Do not attempt this recipe with any other type of flour, or it won't work!