Preheat your oven to 350°F (175°C). Grease and flour two 9-inch round cake pans.

In a large mixing bowl, whisk together the flour, sugar, baking powder, baking soda, and salt.

Add the softened butter, eggs, buttermilk, and vanilla extract to the dry ingredients. Beat on medium speed until the mixture is creamy and smooth.

Carefully fold in the finely chopped pistachios until evenly distributed.

Pour the batter evenly into the prepared cake pans and smooth the tops with a spatula.

Bake for 25-30 minutes, or until a toothpick comes out clean from the center. Allow the cakes to cool in the pans for about 10 minutes, then transfer to wire racks to cool completely.

In a clean mixing bowl, whip the heavy cream and powdered sugar until it forms stiff peaks.

In another bowl, mix together the softened cream cheese and a little bit of whipped cream until smooth.

Gently fold the remaining whipped cream into the cream cheese mixture. Spread a generous amount of frosting between the cooled cake layers and on the top and sides.

Sprinkle the remaining chopped pistachios over the top for an elegant finish.