Preheat the oven to 350°F (175°C). Grease and flour a baking pan.

In a mixing bowl, cream together the softened butter and granulated sugar until light and fluffy.

Add the eggs one at a time, mixing well after each addition. Stir in the vanilla extract.

In another bowl, combine the flour, ground pistachios, baking powder, and salt.

Gradually add the dry ingredients to the wet mixture, mixing until just combined.

Pour the batter into the prepared baking pan and smooth the top.

Bake for 25-30 minutes or until a toothpick inserted in the center comes out clean.

Allow the cake to cool in the pan for 10 minutes before transferring to a wire rack to cool completely.

In a mixing bowl, beat together the softened cream cheese and butter until smooth.

Gradually add the powdered sugar and vanilla extract, mixing until well combined and fluffy.

Once the cake is completely cooled, spread the frosting evenly over the top.

Garnish with additional ground pistachios if desired.