Beat the butter and powdered sugar together until smooth and creamy, about 2 minutes.

Mix in the rose water.

Add the flour and salt, mixing on low speed just until a soft dough forms.

Fold in half the chopped pistachios by hand.

Shape the dough into a log about 2 inches across, rolling it in granulated sugar and the remaining pistachios so they stick to the outside.

Wrap tightly in plastic wrap and chill for at least 1 hour, or until firm enough to slice cleanly.

Preheat the oven to 325°F and line a baking sheet with parchment paper.

Slice the log into rounds about 1/3 inch thick and arrange them 1 inch apart on the sheet.

Bake for 14 to 16 minutes, until the edges are just turning pale gold while the centers stay light.

Cool on the sheet for 5 minutes, then move to a wire rack to cool fully, about 15 minutes, before stacking.