Pulse your unsalted pistachios into fine crumbs using a blender, leaving a few small chunks. Look at the process click above in this post.
Line a pan with 10 cupcake liners and set it aside. Preheat oven to 350°F (177°C).
Beat butter using a hand held or a stand mixer with paddle attachment for a minute. Add in sugar and beat until creamy and fluffy on high. About 2 more minutes.
Add in egg, extracts and beat in to combine. Now mix in sour cream and beat it in too. Next fold in pistachio crumbs in the batter.
Now sift dry ingredients (flour, baking powder, baking soda and salt) over wet and fold everything in pouring milk slowly. Batter will look creamy and thick.
Divide batter in the prepared liners and bake for 20-22 minutes. Or till they pass the toothpick test. Allow them to cool before frosting