These are typical little cookies from Sicily, particularly well known around the area of Bronte near Mount Etna, where they produce Italy's best pistachios. Make sure to start with raw (not toasted) unsalted pistachios—it helps, too, if they already have been popped out of their shells. The skins on or off make little difference.
The most traditional recipes call for equal weights of sugar and pistachios, but the Sicilians do have quite the sweet tooth. I find that nearly half the amount of sugar is already sweet enough.
Note that when adding the egg white, start with just one, beaten, and add it a little at a time before cracking and separating your second egg white, as you may not even need it. Stir with a wooden spoon until it comes together into a batter thick enough that you can either roll it or scoop it (using a teaspoon) into balls.
Sometimes they are rolled in powdered sugar as they are being formed into little balls, which forms pretty little cracks in the cookies as they bake. Sometimes they can be decorated with a little glaze of melted dark chocolate (this one is just perfect: https://food52.com/blog...). Sometimes a little cinnamon or cardamom is added in the mixture for a bit of extra spice. And always you can enjoy them with a glass of some sticky and sweet wine after dinner or with tea and coffee at any time of the day. —Emiko
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