Preheat oven to 350°F (175°C) and grease a 9-inch cake pan.
Grind pistachios into a fine powder and set aside.
In a bowl, mix flour, baking powder, baking soda, and salt.
Cream butter and sugar until light and fluffy.
Add eggs one at a time, then stir in vanilla.
Mix in ground pistachios and dry ingredients alternately with milk and yogurt.
Pour batter into prepared pan and smooth the top.
Bake for 30–35 minutes or until a toothpick comes out clean.
Cool in pan 10 minutes, then transfer to a wire rack to cool completely.
