Grind the pistachios, almond flour, and powdered sugar in a food processor. Transfer this mixture to a large mixing bowl. To make the Italian meringue: In a saucepan, combine the water and granulated sugar and heat until it reaches 246°F (119°C). Meanwhile, place 2.5 ounces (75 grams) of egg whites in a stand mixer bowl. When the syrup reaches 237°F (114°C), start beating the egg whites on high speed. Once the syrup reaches 246°F (119°C), slowly pour it down the side of the mixer bowl onto the whipped egg whites and beat on high speed.

Continue beating until the meringue is cool, smooth, and glossy. Meanwhile, add the remaining 2.5 ounces (75 grams) of egg whites to the almond-sugar mixture you prepared earlier. Mix well until it forms a marzipan-like paste. Gently fold the Italian meringue into the almond paste, being careful not to overmix or the batter will deflate. Pipe two discs onto parchment paper and bake for 15 to 20 minutes at 340°F (170°C).

Prepare the pistachio filling: In a heatproof bowl set over a double boiler, whisk together the eggs, egg yolk, and sugar until the mixture is hot and pale. Remove from the heat and continue whisking to cool it down. Gradually add the softened butter, whisking until smooth and combined. Cover the cream and let it sit at room temperature. Whisk the pastry cream (about 180 grams) to loosen it. Whisk the buttercream, then add the pastry cream and pistachio paste.

Mix until smooth and fully combined.

Assembly: Pipe the pistachio buttercream over the surface of one macaron disc. Add a little raspberry jam between the lines of cream and place fresh raspberries around the edge of the disc. Place the second macaron disc on top to close the macaron, then refrigerate. Remove the macaron from the fridge 15 minutes before serving.