You can buy almonds already sliced, or do it yourself using a food processor fitted with a slicing disk. To sliver a blanched almond yourself, use a paring knife to cut it lengthwise into several small sticks. Less common are black walnuts , which are much more flavorful but harder to shell. To roast, put shelled walnuts on a baking pan and in bake them in a 325 oven, stirring occasionally, until they're slightly golden, about ten minutes. After you remove the nuts from the oven, rub them vigorously with a towel so as to remove as much of their bitter skins as possible.
Fresh walnuts are available year-round, but they're best in the fall.
Since they're high in fat and therefore prone to rancidity, it's best to store them in the refrigerator or freezer. This black nut bears an unmistakable resemblance to a bull's head. Each one is about two inches across, and has a very hard shell. After you shell water caltrops, you'll need to steam or boil them before you can eat them as they contain harmful toxins in their raw state. Or you can skip eating them altogether, and just use them to make jewelry.