Preheat the oven to 300°F. Separate the eggs and retain only the egg whites — make absolutely sure there is no yolk, or the whites will not whip up properly.

In the bowl of a stand mixer fitted with the whisk attachment, beat the egg whites until foamy, about one minute. Add in the meringue powder (optional).

Slowly add the granulated sugar in three increments, mixing well on medium speed after each addition. Once all the sugar is incorporated, increase the speed to medium-high and mix for about 5 more minutes, until the mixture forms very stiff peaks and balls up in the whisk, pulling away from the sides of the bowl.

Add in the green gel food coloring, starting with a few drops and adding more until the desired color is achieved. Mix until evenly colored.

Meanwhile, combine the almond flour and powdered sugar in a fine mesh sifter and gently sieve into a bowl, discarding any larger chunks that remain.

Pour the sifted dry ingredients into the whipped meringue and stir only enough to incorporate — do not overmix at this stage.

Begin the macaronage: slowly fold the batter, deflating the mixture and scraping the bottoms and sides of the bowl to ensure no dry ingredients are hiding. Treat it gently — this is not the time to take out your aggression! Check the consistency frequently.

To test the batter, pull a scoop up with your spatula and let it drop back into the bowl. When ready, it should flow off the spatula in a ribbon and re-incorporate back into the mixture within about a 20-second count — the consistency of lava. Too few folds = tall macarons with a peak. Too many folds = flat macarons that spread outward.

Transfer the batter to a pastry bag fitted with a large round metal tip (or a Ziploc bag with the corner cut). Prepare your baking sheet by turning it upside down if it has a rim, then place your silicone macaron mat or parchment paper template on top.

Holding the bag about ½ inch above the template and perpendicular to the pan, pipe rounds using the center as a bullseye. Squeeze slowly and steadily until the batter reaches the inner circle, then stop pressure and disengage with a gentle swirl. The batter should settle to the outer line. Pipe all rounds until all batter is used.

Firmly tap the entire baking sheet on the counter several times to release any air bubbles. Pop any stubborn bubbles with a toothpick.

Allow the piped rounds to rest for at least 30 minutes (longer in humid climates). The tops should no longer be sticky or tacky to the touch. Test by gently touching one — if it sticks to your finger, it needs more time.

Bake for 10 minutes. If baking more than one tray at a time, rotate the pans halfway through. Let the shells cool completely on the pan before removing.

Once fully cooled, very gently remove the shells from the baking sheet. Store in an airtight container stacked on their sides until ready to fill.

Reserve about 2 tablespoons of the white chocolate chips and set aside for the drizzle. In a microwave-safe bowl, combine the remaining white chocolate chips and heavy cream. Microwave for 1 minute, then remove and stir thoroughly. If needed, heat in additional 15–30 second increments, stirring well each time, until all chips are melted and the mixture is completely smooth.

Add a few drops of green food coloring and stir until smooth and evenly colored.

Transfer the ganache to the bowl of a stand mixer and allow to cool completely to room temperature. If it is warm at all, it will not whip properly.

Meanwhile, use a food processor to grind the pistachios into a very fine paste consistency. Set aside.

Once the ganache has cooled to room temperature, use the whisk attachment to whip it to a frosting-like consistency — about 2–3 minutes on medium speed.

Add the ground pistachios to the whipped ganache and mix well until fully combined. Transfer to a piping bag.

Lay out all the macaron shells and pair them up by similar size. In a microwave-safe bowl, melt the reserved white chocolate chips in 15-second increments, stirring until smooth. Transfer to a small piping bag and allow to cool slightly.

Cut a small hole in the end of the white chocolate bag and pipe a decorative drizzle over one side of half the shells (these will be the tops). Immediately sprinkle with crushed pistachio crumbs. Allow to set.

For the remaining shells, place them bottom-side up on your work surface. Pipe a generous mound of whipped pistachio ganache onto each one.

Place the decorated top shell on top of each ganache-filled bottom shell to create the sandwich. Press gently to adhere.