Line a 30cm x 23cm x 4cm baking tin. Put the can of coconut milk in the freezer for a maximum of 1 hour 15 minutes.
Blend the dates, walnuts and oats in a food processor until you get damp crumbs. You should be able to press the crumbs together with your fingertips as if it’s a dough. Tip into the lined tin and flatten out with your fingertips until it creates an even layer. Transfer to your freezer for 20 minutes. Drain the cashews and set aside.
Remove the coconut milk from the freezer, being careful not to turn it upside down or shake it. Carefully open and scoop out the set coconut milk from the top of the can and add to a food processor, discarding any water left over. Beat until smooth and creamy. Add 300ml agave syrup and scrape in the seeds from the vanilla pod, discarding the pod. Beat until smooth. Add the soaked cashews and blend for 4-5 minutes until smooth and creamy.
Transfer half the mixture to a large bowl and cover. Add 3 tbsp cacao powder to the food processor and process briefly until combined. Remove the base from the freezer and pour on the cacao filling. Spread until smooth and even and place back in the freezer for an hour.
While the first layer of the cheesecake sets, blitz 125g raspberries with 2 tbsp water until smooth. Remove the tray from the freezer and pour on the vanilla layer. Smooth out until even, then add the raspberry purée. Swirl around creating a pattern, then dot on the remaining raspberries. Transfer to the freezer for 3-4 hours.
In a small saucepan, combine the coconut oil and the remaining agave. Heat until the coconut oil has melted, then add the remaining cacao powder. Stir until combined, then remove from the heat. Leave for 5 minutes to cool slightly then drizzle over the cheesecake – it should start setting immediately. Cut the cheesecake into bars and serve.