Grease a 6 inch springform pan with coconut oil, or line a 6 inch cake pan with parchment paper for easy removal. I would recommend greasing it as well.
Make the crust: To a food processor, add the walnuts, almond flour, dates, 2 tablespoons water and salt. Process until a sticky dough is formed, adding another tablespoon of water (or more) if needed. Do not over process. Press the dough evenly along the bottom of the prepared pan.
Make the first layer: To a high powered blender, add the soaked cashews, coconut milk, agave or maple syrup, lemon juice and vanilla. Blend for about 2 minutes, stopping the scrape the sides of the blender as needed. Blend until very smooth and creamy.
Pour 2/3 of the filling on top of the crust in the pan. Place in the freezer while you make the next layer.
Make the second layer: Add the 1/2 cup raspberries to the remaining mixture in the blender, and blend until incorporated. Pour this on top of the first white layer, and return it to the freezer.
Make the third layer: Quickly rinse out the blender, and add the 1 cup raspberries, lemon juice, agave/maple and chia seeds (the tart raspberry top layer ingredients). Blend until smooth, and pour over the other layers.
Return to the freezer, and let set for at least 3 hours (overnight preferred). To serve, gently remove from pan and run a large heavy knife under hot water for a minute before cutting the cheesecake with the warm, dry knife. You can also let it thaw to room temperature for 10-15 minutes to make it easier to cut.
Store leftovers in the fridge for a couple of weeks, but make sure to wrap it well to avoid freezer burn. Top with more fresh raspberries, if desired.