Preheat your oven to 350°F (175°C). Combine digestive biscuit crumbs, finely chopped roasted pistachios, and melted unsalted butter in a mixing bowl until it resembles wet sand. Press into a lined square baking dish and bake for 10 minutes. Let cool.

In a saucepan over medium heat, combine fresh raspberries, white sugar, and cornstarch. Stir until bubbling and thickened (5-7 minutes). Remove from heat and cool completely.

In a large bowl, beat together softened cream cheese, powdered sugar, and vanilla extract until smooth. Fold in whipped heavy cream until just combined.

Spread half of the cream cheese mixture over the cooled crust. Layer the cooled raspberry mixture on top, followed by the remaining cream cheese mixture. Smooth the top.

Cover with plastic wrap and refrigerate for at least 4 hours. Slice into squares, garnish with raspberries and chopped pistachios, and dust with powdered sugar before serving.