Prepare the Crust: Begin by preheating your oven to 350°F (175°C). In a bowl, mix the crushed graham crackers, melted butter, and granulated sugar until everything is well combined. Press this mixture firmly into the bottom and up the sides of a pie dish. Bake for 8-10 minutes until lightly golden. Set aside to cool.
Make the Filling: While the crust is cooling, blend the shelled pistachios in a food processor until finely ground. In a separate bowl, beat the heavy cream until stiff peaks form.
Combine Ingredients: In a mixing bowl, combine the sweetened condensed milk, gelatin (prepared according to package instructions), ground pistachios, vanilla extract, and powdered sugar. Gently fold the whipped cream into this mixture until everything is well blended.
Assemble the Pie: Pour the creamy filling into the cooled crust, smoothing it out. Refrigerate the pie for at least 4 hours, preferably overnight, to allow it to set properly.
Serve: Before serving, garnish with whipped cream and a sprinkle of crushed pistachios. Cut into slices and enjoy!