pistachio macarons

Pistachio Macaron Batter:

• 1 ¼ cups confectioner's sugar
• 4 oz pistachios
• ¼ cup plus 2 tbsps egg whites at room temperature
• pinch of salt
• ¼ cup sugar
• a few drops of green food coloring (optional)

Pistachio Filling:

• 1 1/2 oz pistachios
• 1 c confectioner's sugar
• 6 tbs softened butter
• 1/2 tsp vanilla extract

Preheat your oven to 350F. Line 2 baking sheets with parchment paper.
Process the pistachios with powdered sugar until you get fine pistachio flour. (I processed for 3 1-minute intervals mixing with a spatula between each.)
In a greaseless bowl, combine the egg whites with the pinch of salt. Beat on medium power until soft peaks start to form. Increase the speed, gradually beat in the sugar and continue to whip until stiff and firm peaks form, about 2 minutes. Sieve the pistachio flour and fold it into the egg whites in two batches, mixing with a spatula just until no streaks remain. This will seem to be a lot of pistachio flour for the amount of egg whites you have, but it will work out.  If you want your macarons more green add some food coloring.
Scrape the batter into a pastry bag with a round tip. Pipe 1" circles of macaron batter about 1" apart on parchment lined baking sheets. Rap the baking sheets firmly on the table to remove air bubbles. Let rest for about an hour until the macarons develop a skin. Bake for 10 minutes.
For the filling, process the pistachios and the confectioner's sugar just like you did for the macaron batter. Cream this with the softened butter until uniformly mixed.
Cool the macarons completely before you remove them from the parchment. Pair similar sized ones and glue them with some pistachio filling.