01 - Preheat oven to 225°F. Line two baking sheets with parchment paper.
02 - In a clean bowl, beat egg whites until foamy. Add cream of tartar and continue beating until soft peaks form.
03 - Gradually add granulated sugar, 1 tablespoon at a time, beating until stiff, glossy peaks form and sugar is dissolved. Beat in vanilla extract.
04 - Gently fold in the finely ground pistachios with a spatula.
05 - Spoon or pipe the meringue into 8 nests (about 3 inches wide) on the prepared baking sheets, creating a small well in the center of each.
06 - Bake for 1 hour 30 minutes, rotating the trays halfway, until dry and crisp. Turn off oven, crack oven door, and let nests cool completely inside.
07 - For the filling, whip the heavy cream with powdered sugar and vanilla extract until soft peaks form.
08 - Fill each cooled meringue nest with whipped cream. Top generously with raspberries and sprinkle with chopped pistachios.
09 - Garnish with mint leaves if desired. Serve immediately for best texture.