Cream together 1 cup of softened unsalted butter and 1 cup of sugar until light and fluffy, about 3 to 5 minutes. Add pistachio pudding mix and 2 beaten eggs and mix until smooth.

In a separate bowl, whisk together 2 cups of all-purpose flour and 1 teaspoon of baking powder. Gradually add to the wet dough and stir gently until no visible flour remains.

Fold in 1 cup of coarsely chopped roasted pistachios into the dough and mix until evenly distributed.

Cover and refrigerate the dough for at least 30 minutes. Preheat oven to 350°F (175°C).

Scoop tablespoon-sized portions onto a lined baking sheet, leaving space for spreading. Bake for 10 to 12 minutes until edges are golden and centers set.

Let cool on the baking sheet for about 5 minutes, then transfer to a wire rack. Dust with powdered sugar before serving.