Preheat the oven and prepare a cake pan.

In a bowl, combine the flour, ground pistachios, granulated sugar, and baking powder.

In another bowl, cream the softened butter and sugar until light and fluffy.

Add the eggs one at a time, mixing well after each addition.

Stir in the vanilla extract and milk.

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

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

Bake in the preheated oven for 30 minutes or until a toothpick comes out clean.

Allow the cake to cool before frosting.

For the frosting, beat together the powdered sugar, softened butter, vanilla extract, and enough milk to achieve desired consistency.

Frost the cooled cake and garnish with extra ground pistachios.