01 - Preheat oven to 225°F. Line two baking sheets with parchment paper.
02 - Using a spotlessly clean bowl and electric mixer, beat egg whites until foamy. Add cream of tartar and continue beating until soft peaks form.
03 - Gradually add granulated sugar one tablespoon at a time, beating continuously until stiff, glossy peaks form and sugar is completely dissolved. Mix in vanilla extract.
04 - Gently fold the finely ground pistachios into the meringue using a spatula, being careful not to deflate the mixture.
05 - Spoon or pipe the meringue into 8 nests approximately 3 inches wide on prepared baking sheets, creating a shallow well in the center of each.
06 - Bake for 1 hour 30 minutes, rotating baking sheets halfway through cooking, until meringues are completely dry and crisp to the touch.
07 - Turn off oven, crack door slightly open, and allow meringue nests to cool completely inside the oven to prevent cracking.
08 - Whip heavy cream with powdered sugar and vanilla extract using electric mixer until soft peaks form and cream holds its shape.
09 - Fill each cooled meringue nest with whipped cream, top generously with fresh raspberries, and sprinkle with chopped pistachios. Garnish with mint leaves if desired.
10 - Serve immediately for optimal texture, as meringue begins to soften once filled with cream.