Melt the butter and combine it with the ground biscuits and milk until evenly moistened.

Press the biscuit mixture firmly into the base of the 24 cm springform pan.

Cook the blueberries with 100 ml water, granulated sugar, and vanilla sugar until the berries break down into a sauce.

Whisk the cornstarch with a small amount of water, then stir it into the berry sauce.

Cook the berry filling briefly until thickened, then spread it immediately over the biscuit base.

Cool the berry layer until no longer hot before adding the cream.

Whip the whipping cream to stiff peaks using the electric hand mixer.

Add mascarpone and 200 g pistachio cream, then mix until smooth and fully combined.

Fold in the chopped pistachios, then spread the cream gradually over the cooled berry layer to avoid trapping air.

Gently melt the remaining 200 g pistachio cream and pour it evenly over the cheesecake.

Chill the cheesecake until set before slicing and serving.