Prepare the Cookie Dough

1. Preheat Oven: Preheat your oven to 350°F (175°C) and line a baking sheet with parchment paper.
2. Combine Dry Ingredients: In a medium bowl, whisk together the flour, ground pistachios, baking powder, and salt. Set aside.
3. Cream Butter and Sugar: In a large mixing bowl, beat the softened butter and granulated sugar together until light and fluffy, about 2-3 minutes.
4. Add Wet Ingredients: Beat in the egg, vanilla extract, and rosewater until fully incorporated.
5. Mix Dry Ingredients: Gradually add the dry ingredients to the wet ingredients, mixing until just combined. The dough should be soft but not too sticky.
6. Chill the Dough: Wrap the dough in plastic wrap and refrigerate for at least 30 minutes to firm it up, making it easier to roll out.

Shape and Bake the Cookies

1. Roll Out the Dough: On a lightly floured surface, roll the chilled dough to about ¼-inch thickness.
2. Cut the Cookie Shapes: Using a tree-shaped cookie cutter, cut out the cookies and place them on the prepared baking sheet. If the dough becomes too soft while rolling, return it to the fridge for a few minutes to chill.
3. Bake the Cookies: Bake the cookies in the preheated oven for 12-15 minutes, or until the edges are lightly golden.
4. Cool: Remove the cookies from the oven and allow them to cool on the baking sheet for a few minutes before transferring them to a wire rack to cool completely.

Make the Rose Glaze

1. Prepare the Glaze: In a small bowl, whisk together the powdered sugar, milk, and rosewater until smooth. Add a few drops of pink food coloring if desired to give the glaze a festive look.
2. Glaze the Cookies: Once the cookies are completely cool, drizzle the rose glaze over the tops or dip the tops of the cookies into the glaze.