Preheat your oven to 350°F (175°C). Line a muffin tin with paper liners or grease the tin.
In a medium-sized bowl, whisk together the flour, baking powder, salt, and ground pistachios.
In a large bowl, cream together the butter and sugar until light and fluffy.
Add eggs, one at a time, mixing well after each addition. Stir in vanilla extract.
Gradually add the dry ingredients into the wet mixture, alternating with milk, and mix until just combined.
Gently fold in the chopped pistachios.
Spoon the batter evenly into the muffin tin, filling each cup about ¾ full.
Bake for 18-22 minutes or until a toothpick inserted comes out clean.
Allow the muffins to cool on a wire rack before serving.