Make the cake: In a large bowl place cream cheese and powdered sugar. Mix until smooth. Add pistachio paste, vanilla bean paste and mix until smooth.
Add heavy cream and whip to stiff peaks. Set aside.
Dip each biscuit into the milk for 1-2 seconds, then arrange at the bottom of a 20X30cm (8X12-inch) pan. Spread half of the cream on top of the biscuits. Then arrange another layer of dipped biscuits. Spread the remaining cream on top.
Cover and refrigerate for at least 4 hours or overnight.
Make the pistachio ganache: place white chocolate in a heatproof bowl, add heavy cream and heat in the microwave in 20-30 second pulses until melted. Stir until smooth. Add pistachio paste and stir until smooth.
Spread the ganache on top of the cake. And refrigerate until ready to serve.
Decoration: just before serving crush pistachios and sprinkle them on top of the ganache.