Soak the cashews in filtered water for 2-4 hours. Drain and rinse the cashews, then add to an upright, high-speed blender along with the fresh water. Blend on high speed for about 2 minutes, until the cashews are completely blended and you have a creamy, frothy milk. Add the dates, salt, cinnamon, maple syrup, coconut oil and vanilla, and blend for another 30 seconds, or until completely combined.
Place the chia seeds in a large mixing bowl, and pour the cashew milk over top, stirring to combine. The mixture will begin to thicken. Let sit for 15 minutes, stirring a few times to prevent clumping, then refrigerate for at least 2 hours to set up completely (or preferably overnight). You’ll know the chia pudding is ready when the mixture is thick and creamy, and there are small, tapioca-like chia balls throughout. If the gel texture freaks you out, you can also blend the pudding once set, until smooth. The chia pudding can be made up to five days in advance, kept in an airtight container in the refrigerator. It may continue to thicken a bit. Divide among bowls and serve with the raspberry rhubarb compote drizzled on top.
Raspberry Rhubarb Compote
Add the water and sugar to a medium pot set over medium-high heat, and stir to dissolve the sugar. Bring just to a boil, add the raspberries, cook for a minute or two, then turn the heat down to medium-low, and simmer for 5-10 minutes, stirring regularly, until the raspberries have mostly broken down. Use the back of a spatula or wooden spoon to smash the berries, until a thick sauce forms.
Optional: Remove the raspberry sauce from the heat, and pour through a fine-mesh strainer into a bowl to strain out the raspberry seeds. Press gently with the back of a spoon to release as mich juice as possible. Return the raspberry sauce to the pot.
Stir in the vanilla extract, and add the chopped rhubarb. Let gently simmer for 5-10 minutes, until the rhubarb is tender and can be easily pierced with a fork. Remove from the heat and let cool to room temperature. To serve, divide the rhubarb between the chia pudding bowls and drizzle with remaining syrup. The compote can be made a day or two in advance, kept in an airtight container in the refrigerator.