Prepare the dough. Place the ghee and powdered sugar in a large bowl and mix with your hands until well combined. Gradually add the flour, mixing with your fingertips. The mixture may initially look crumbly, but continue kneading until the dough comes together and becomes smooth and pliable. Alternatively, you can use a stand mixer. Cover the dough with plastic wrap and refrigerate for 30 minutes.
Preheat the oven. Preheat the oven to 150°C (300°F), with a rack positioned in the center.
Prepare the baking sheets. Line two baking sheets with parchment paper.
Shape the Ghraybeh. Remove the dough from the refrigerator and knead it gently until pliable. Take a piece of dough roughly the size of an apricot and roll it between your palms into a rope about 5 cm (2 inches) long. Bring the ends together and gently pinch them to form a ring.
Arrange and decorate. Carefully transfer the cookies to the prepared baking sheets, spacing them about 1 inch apart. Place a piece of pistachio where the ends meet, or leave the cookies plain if you prefer.
Bake the cookies. Bake one sheet at a time on the center rack for approximately 18 minutes. Ghraybeh should remain pale, almost snow-white, when baked. Baking at a low temperature helps the cookies cook through without becoming too brown. Since oven temperatures vary, keep a close eye on them; the bottoms should be only lightly golden.
Cool before handling. The Ghraybeh will be slightly soft when they come out of the oven but will firm up as they cool. Avoid touching or moving them while they are still hot, as they are delicate and can break easily.