Place the cashews in a bowl and cover with water; soak for 2 hours.
Preheat the oven to 350F. Place the pecans on a baking sheet and bake for 10 minutes, then remove from the oven and cool for a minute or two. In a food processor, blend the pecans, oats, coconut oil, maple syrup, and kosher salt. Blend until fully pulverized and a sticky mixture forms, scraping down as necessary.
In a non-stick mini muffin tin (spray or oil the tin if not non-stick), place a heaping ½ tablespoon of the crust mixture into each cup and pack it down, to make 20 in all (leave the last 4 cups empty). Save the remainder of the crust for the topping.
Wipe out the bowl of the food processor. Drain the berries. In the food processor, blend the soaked cashews, ¾ cup blackberries, maple syrup, coconut oil, vanilla extract, and balsamic vinegar. Blend for several minutes until very smooth and creamy.
Place the remaining berries in a bowl and very gently drizzle them with a glug of maple and a small sprinkle of balsamic vinegar.
To the mini muffin tin, add a heaping tablespoon of the blackberry filling on top of each crust. Garnish each with the remaining crust crumbles and 1 blackberry. (Save the remaining blackberries for future use.)
Freeze the cheesecakes for 1 hour until set, then transfer them to the refrigerator until serving. To remove, use a spoon or sharp small knife to release one edge of the cheesecake by pulling towards you, which should release the remaining sides and twist the cheesecake out of the tin. Serve chilled for best results (cheesecakes can sit at room temperature, but the texture becomes looser as they sit). Remaining cheesecakes can be frozen for 1 to 2 months; thaw in the refrigerator before serving.