Line 2 cookie sheets with parchment paper.

Sift the powdered sugar and almond flour together into the bowl of meringue. Turn the mixer on low for 10 to 15 rotations until the dry ingredients start to blend into the meringue. Pulse the mixer on medium­/high 4 to 5 times to incorporate the batter.

Remove the mixing bowl from the mixer, and gently stir the batter with a spatula just until there are no pockets of egg whites or dry bits of almond flour. Don’t overstir. Trans­fer the batter to a piping bag fitted with Ateco tip #804.

Pipe the macaron batter onto the prepared cookie sheets (30 should fit on each cookie sheet). Holding a cookie sheet firmly in both hands, and making sure the parchment paper doesn’t slide around, bang the cookie sheet on the counter a few times. Rotate the cookie sheet and bang it a few more times. Repeat with the other cookie sheet. This will smooth out the batter and will help form the macarons’ famous “feet.” Sprinkle the chopped pistachios on top of the macs.

Let rest for 45 minutes, or until the rounds of batter have formed shells.

Preheat the oven to 350°F.

Bake for 10 minutes or until the macs look dry and the shells look shiny. Let cool completely on the cookie sheets.

To make the filling: In the bowl of a stand mixer fitted with the paddle attachment, add the powdered sugar, butter, Dutch cocoa powder, milk, and pistachio extract. Mix on low until combined, then speed mixer up to high for 1 minute or until light and fluffy. Transfer to a piping bag with no tip.

Turn over every other macaron and pair them together. Pipe a dollop of filling onto each turned over macaron and sandwich together.

Serve or eat immediately!