Pre-heat oven to 400oF.
In a medium-sized bowl, combine the flour, salt, baking powder, and finely chopped pistachios. Whisk them together then set them aside.
In another large bowl, using a mixer, cream the butter and sugar for 2 to 3 minutes or until it becomes fluffy and light. Add the eggs one at a time, mixing them well. Add the vanilla and yogurt. Mix until all ingredients are combined.
Pour the wet ingredients into the dry ingredients. Stir gently with a spatula.
Spoon the batter into the muffin tins previously sprayed with non-stick spray.
Sprinkle the top with the coarsely chopped pistachios.
Bake the muffins into the preheated oven for about 5 minutes. Lower the temperature to about 350oF and continue to bake for about 15 minutes.
Remove the muffins from the oven and allow to cool.