Combine the all-purpose flour, icing sugar, hazelnut flour, and salt in a mixing bowl.

Rub 125 g cold butter into the dry ingredients until the mixture resembles fine sand.

Add the egg and mix just until a cohesive pastry dough forms.

Flatten the dough into a disc and refrigerate it for at least 60 minutes.

Roll the chilled dough to a 3 mm thickness and line a tart pan with it.

Prick the pastry base with a fork and bake it at 170°C / 340°F until golden.

Cool the baked tart shell completely before adding the fillings.

Chop 100 g dark chocolate and place it in a heatproof mixing bowl.

Heat 100 ml fresh cream until steaming and pour it over the dark chocolate.

Whisk the dark chocolate mixture until smooth and pour it into the cooled tart shell.

Chop 100 g white chocolate and place it in a clean mixing bowl.

Soak 4 g sheet gelatin in cold water until softened.

Bring 100 ml fresh cream to a boil and pour it over the white chocolate.

Add the softened gelatin and whisk until it has completely dissolved.

Add 50 ml cold fresh cream and blend the mixture until emulsified.

Cover the vanilla ganache directly on its surface and refrigerate it for at least 240 minutes.

Whip the chilled white chocolate ganache until thick and mousse-like.

Pipe or spread the whipped ganache over the dark chocolate ganache.

Decorate the crostata generously with fresh raspberries and chill before serving.