1. Preheat your oven to 350°F and line two baking sheets with parchment paper.
2. In a medium bowl, whisk together the flour, baking powder, and salt. Set aside.
3. In a large bowl, cream the butter, granulated sugar, and powdered sugar until light and fluffy, about 3-4 minutes. Remember, patience here makes all the difference!
4. Add the vanilla extract and mix until combined.
5. Gradually add the dry ingredients to the wet ingredients, mixing until just combined.
6. Stir in the chopped pistachios, ensuring they’re evenly distributed throughout the dough.
7. Scoop tablespoons of dough onto the prepared baking sheets, spacing them about 2 inches apart.
8. Bake for 10-12 minutes, or until the edges are lightly golden. Let them cool on the baking sheet for 5 minutes before transferring to a wire rack to cool completely.
9. For the filling, beat together the heavy cream, cream cheese, and powdered sugar until smooth and creamy. Gently fold in the chopped pistachios.
10. Once the cookies are completely cool, spread a generous amount of filling on the underside of one cookie and top with another to form a sandwich.

These cookies are a delight to make, and I often find myself sneaking a taste of the filling—a little perk of being the chef!