PISTACHIO - COCOA NIB MACARONS WITH BITTER CHOCOLATE GANACHE

Ingredients :
(Recipe adapted from here)

For the shells:
200 gr powdered sugar
55 gr almonds (slivered, blanched, sliced, whatever you like)
55 gr pistachios (roasted, unsalted)
90 gr egg whites (use egg whites that have been preferably left 3-4 days in the fridge)
25 gr granulated sugar
1/2 cup cocoa nibs

For the buttercream:
(I omitted this and replaced buttercream with bitter chocolate ganache. Refer to recipe here)
3 egg yolks
1/2 cup sugar
1/4 cup water
1 1/2 sticks unsalted butter, at room temperature
2-3 tablespoons Bourbon

Prepare the macarons:
Place the powdered sugar, almonds and pistachios in a food processor and give them a good pulse until the nuts are finely ground. Sift if desired.
In a stand mixer fitted with the whisk attachment, whip the egg whites to a foam, (think bubble bath foam) gradually add the sugar until you obtain a glossy meringue (think shaving cream). Do not overbeat your meringue or it will be too dry.
Add the nuts and powdered sugar to the meringue, give it a quick fold to break some of the air and then fold the mass carefully until you obtain a batter that falls back on itself after counting to 10. Give quick strokes at first to break the mass and slow down. The whole process should not take more than 50 strokes. Test a small amount on a plate: if the tops flattens on its own you are good to go. If there is a small beak, give the batter a couple of turns.
Fill a pastry bag fitted with a plain tip (Ateco #807 or #809) with the batter and pipe small rounds onto parchment paper or silicone mats lined baking sheets. Sprinkle with cocoa nibs. Let the macarons sit out for 30 minutes to an hour to harden their shells.
When you are ready to bake, preheat the oven to 280F.
Bake the macarons for 15 to 20 minutes, depending on their size. Let cool.
Once baked and if you are not using them right away, store the shells in an airtight container out of the fridge for a couple of days or in the freezer for up to 2 weeks (longer and the sugar starts to seep out which makes them sticky).

Prepare the buttercream:
(I omitted this and replaced buttercream with bitter chocolate ganache. Refer to recipe here)
Place the yolks in a stand mixer, fitted with the whisk attachment.
Bring the sugar and water to 238F in a medium saucepan set over high heat. Slowly pour the hot syrup over the egg yolks and continue to whisk until cold. Change to the paddle attachment and beat in the butter, one tablespoon at a time. Add the bourbon to the buttercream. Continue to beat for a few seconds until completely smooth.

Assemble the macarons:
Fill the macarons with the buttercream (pipe or spoon about 1 tablespoon per macaron) and store in the fridge for at least 48 hours before eating (the shell should be crisp without shattering in your hands and the center soft without being too mushy).