Preheat your oven to 180°C (350°F) and prepare an 18 cm round pan by lining the base with parchment paper.

Combine ground biscuits, ground pistachios, and melted unsalted butter in a mixing bowl until it resembles wet sand. Press evenly into the base of the prepared pan.

Bake in the preheated oven for about 12.5 minutes until golden, then let cool completely.

Soak gelatin leaves in cold water for about 5-10 minutes. Heat milk with half the caster sugar until simmering.

In a bowl, whisk remaining sugar with egg yolks until creamy, then gradually pour in hot milk while whisking continuously.

Return the combined mixture to the stove, cooking gently until it coats the back of a spoon at around 82°C.

Stir in bloomed gelatin until dissolved. Mix in raspberry puree, then let cool.

Whip heavy cream until soft peaks form. Gently fold into the cooled raspberry mixture, then pour over the biscuit base.

Chill in the refrigerator for at least 2-3 hours until set.

For the pistachio mousse, heat milk with pistachio paste, then whisk with egg yolks and sugar until thickened.

Add bloomed gelatin to the pistachio mixture, cool to room temperature, then fold in whipped cream.

Pour pistachio mousse over the set raspberry layer, smooth the top, and refrigerate overnight.

Remove the cake from the pan, garnish with ground pistachios and fresh raspberries, and serve.