For the Pistachio Cake:

1. Preheat the oven to 350°F. Spray a 9×9 pan with non-stick spray and line it with parchment paper.
2. Grind the pistachios in a food processor until finely ground.
3. In a medium bowl, whisk together flour, baking powder, baking soda, and salt. Set aside.
4. In a large bowl, cream together softened butter and granulated white sugar until fluffy.
5. Add eggs and vanilla, mixing until pale and smooth.
6. Alternate adding buttermilk and dry ingredients to the wet ingredients, mixing until combined.
7. Fold in ground pistachios.
8. Pour batter into the prepared pan and bake for 38-44 minutes, or until a cake tester comes out clean.
9. Let the cake cool completely in the pan on a wire rack.

For the Cream Cheese Frosting:

1. Beat butter in a large bowl until pale and fluffy.
2. Add cream cheese and beat until fluffy.
3. Sift in powdered sugar and mix until combined and fluffy.

For the Pistachio Cream:

1. Grind pistachios in a food processor until they turn into pistachio butter.
2. Whisk together pistachio butter and sweetened condensed milk.
3. Beat heavy cream until firm peaks form, then fold into pistachio mixture.

Assembling the Cake:

1. Once cooled, turn the cake out onto a serving plate. Poke holes in the top of the cake.
2. Pipe pistachio cream into the holes.
3. Frost the top of the cake with cream cheese frosting, swirling in pistachio cream.
4. Sprinkle with chopped pistachios, then serve and enjoy!