These green Middle Eastern nuts are encased in tan shells, which are sometimes dyed red. They're crunchy and delicately sweet, so they're great in everything from ice cream to pilafs. When the nuts are mature enough to eat, the shells split open enough that they can be pulled off easily with your fingers. Unopened shells contain immature kernels and should be discarded. Pistachios are available shelled or unshelled, salted or unsalted, roasted or raw. To roast, put shelled pistachios on a baking pan and in bake them in a 325° oven, stirring occasionally, until they're slightly golden, about ten minutes.