In a medium bowl, whisk flour, baking powder, and salt. Set aside.
In a large bowl, combine water, rosewater, oil, sugar, eggs and salt.
Gradually add the flour mixture to the wet ingredients, stirring until dough forms.
Knead the dough on a flat surface until smooth. Adjust with water or flour if needed for the right consistency.
Roll out half the chilled dough on a floured surface to ⅛-inch thickness. Cut circles with a 3-inch cookie cutter and place on the baking sheet.
Put 1 teaspoon of pistachio spread in the center of each circle. Fold to form a triangle, ensuring the filling is visible in the center. Pinch seams to seal.
Bake for 15-18 minutes until golden. Drizzle baked cookies with additional pistachio spread. Sprinkle with diced pistachios.