01 - Preheat oven to 350°F. Grease a 9-inch round cake pan and line with parchment paper.
02 - Whisk flour, ground pistachios, baking powder, and salt in a bowl. Set aside.
03 - Beat butter and sugar in a large bowl until pale and fluffy, approximately 3 minutes.
04 - Add eggs one at a time, beating thoroughly after each addition. Mix in vanilla extract.
05 - Blend half the dry ingredients into the wet mixture. Add milk, then remaining dry ingredients, mixing until just incorporated.
06 - Gently fold raspberries into the batter, taking care not to crush the fruit.
07 - Transfer batter to prepared pan, smooth the surface, and bake for 38 to 42 minutes until a toothpick inserted into the center comes out clean.
08 - Let cake rest in pan for 15 minutes, then remove and transfer to a wire rack to cool fully.
09 - Dust cooled cake with powdered sugar and sprinkle with chopped pistachios if desired.