For the crust, in a high-speed blender or food processor, pulse the hazelnuts to fine crumbles and transfer to a medium sized bowl. Pulse dates to fine crumbles and add to bowl.
Sift in cacao or cocoa powder, add water and mix well.
Line cake spring-form with baking paper. Scoop dough for the crust into spring-form and spread it evenly, pressing it gently smooth with your (clean) hands.
For the vanilla layer, blend all ingredients until smooth. I find it helps to start with a few pulses until the mixture starts moving. Start with 1/2 cup water and add more if needed.
When smooth, take two teaspoons of it aside and pour the rest of the mixture into the cake tin. Spread evenly. Place in freezer while preparing the raspberry layer.
For the raspberry layer, place raspberries and dates in blender and blend until smooth. Then add cashews and coconut oil and pulse a few times until the mixture starts moving. If needed, add 1/4 cup of water.
Take cake tin out of freezer and pour the raspberry cream over the vanilla layer, spread evenly. Then take the remaining two teaspoon of vanilla cream, add a tiny little bit of water until it is just watery enough to drizzle over the top of the cake in circling motions. Add garnish of your choice (I used freeze-dried raspberries).
Place in freezer until set (approx. 6 hours). Cut slices when it is just soft enough, this way you'll get nice and clean edges.