Preheat the oven to 375°F (190°C). Line a muffin tin with paper or silicone liners.
Combine the flour, ground pistachios, baking powder, baking soda, and salt in a medium bowl.
1 3/4 cup all purpose flour, 3/4 cup shelled pistachios, 1 teaspoon baking powder, 1/2 teaspoon baking soda, 1/4 teaspoon salt
Whisk the sugar and melted butter in a large mixing bowl until smooth. Add the eggs, buttermilk, and vanilla extract and mix well.
2/3 cup sugar, 1/2 cup unsalted butter, 2 large eggs, 3/4 cup buttermilk, 1 teaspoon vanilla extract
Gradually fold the dry ingredients into the wet ingredients until they are combined. Be careful not to overmix. The batter should be thick but smooth.
Divide the batter evenly among the prepared muffin cups, filling each about 2/3 full. Sprinkle the tops with the chopped pistachios.
2 tablespoons chopped pistachios for topping
Bake in the preheated oven for 20-22 minutes or until a toothpick inserted into the center of a muffin comes out clean.
Allow the muffins to cool in the pan for 5 minutes, then transfer them to a wire rack to cool completely.