Preheat oven to 350°F (175°C). Line baking sheets with parchment paper.

In a medium bowl, whisk together flour, baking powder, baking soda, and salt.

In a large bowl, cream the softened butter and granulated sugar until light and fluffy, about 2-3 minutes.

Beat in the pistachio paste until smooth. Add eggs one at a time, then mix in vanilla and almond extracts.

With mixer on low, alternately add the dry ingredients and buttermilk, beginning and ending with dry ingredients. Mix until just combined.

Scoop dough onto prepared sheets, 2 inches apart. Garnish with chopped pistachios if desired. Bake for 10-12 minutes until edges are just set. Cool on sheet for 5 minutes, then transfer to a wire rack to cool completely.

For the filling, beat softened cream cheese and butter until smooth. Gradually add sifted powdered sugar, vanilla, and salt. Beat until fluffy.

Once cookies are cool, spread or pipe filling onto the flat side of half the cookies. Top with remaining cookies to form sandwiches.