Make the pistachio ganache

1. Finely chop the white chocolate and place it in a bowl, then stir in the pistachio paste.
2. Heat the heavy cream in a small saucepan until it just begins to simmer.
3. Pour the hot cream over the white chocolate in three additions, mixing well with a spatula each time until smooth and glossy.
4. Cover the ganache with plastic wrap pressed against the surface and refrigerate for at least 2 hours, or let it firm up at room temperature until ready to use.

Prepare the macaron shells

1. Blend the almond flour and powdered sugar in a food processor until you get a fine, lump-free mixture.
2. In the bowl of a stand mixer, beat the egg whites on medium-low speed until foamy.
3. While mixing, slowly add the granulated sugar, one tablespoon at a time, about every 30 seconds. Once all the sugar is added, increase to medium-high speed and whip until you get a firm French meringue with stiff peaks.
4. Add the green gel food coloring and whip briefly until the color is evenly combined.
5. Gently fold the almond flour mixture into the meringue in one addition using a rubber spatula. Continue folding until the pistachio macaron batter is smooth and flows in a ribbon when lifted.
6. Transfer the batter to a piping bag fitted with a round tip and pipe small rounds onto a baking sheet lined with parchment paper.
7. Let the shells rest at room temperature for 30–45 minutes, or until a skin forms on top.

Bake

1. Preheat your oven to 290–300°F (145–150°C) for at least 20 minutes.
2. Bake the pistachio macarons one tray at a time for 14–15 minutes without opening the oven door.
3. Let the shells cool completely before carefully removing them from the parchment paper.

Fill & decorate

1. Once the shells are cool, pipe the pistachio ganache onto one shell (add a small drop of pistachio spread in the center for extra flavor if you like).
2. Sandwich with a second shell to form the macarons, then refrigerate for at least 2 hours before serving.
3. For decoration, drizzle with melted white chocolate colored and flavored with pistachio, and sprinkle with chopped pistachios.