Drain the soaking water from the cashews and rinse them in fresh water. In a food processor combine cashews, fresh filtered water, miso paste, and probiotic powder until smooth. Be patient, the mixture will get smooth eventually with a little manual labor helping it along. Just stop the food processor every so often and push the mixture off of the sides with a spatula.
Once the mixture is smooth add in the remaining ingredients (except the pistachios) and run the mixture through the food processor again until everything is well combined.
Empty the mixture into 2 layers of cheesecloth. Make sure the cheesecloth is cut big enough to cover the entire cheeseball and have some excess at the top. Tie the excess ends at the top around a wooden spoon or something that can suspend the cheeseball in a large mixing bowl so that it doesn’t touch the bottom of the bowl. Then cover the bowl with a tea towel and leave it in a warm, dark place (in a cupboard, on the counter, or on top of the fridge for 16 hours.
After 16 hours unwrap the cheesecloth and transfer the mixture into a new clean 2 layered cheesecloth. You can reuse these if you just wash them in warm water and a little dish soap and allow them to air dry. Tie this around the wooden spoon again and suspend it the same way in the mixing bowl but keep it in the fridge for 24-48 hours. The longer it sits the more cheesy “fermented” flavor it will develope. Do not leave it more than 36 hours.
When you’re ready to serve the cheeseball, unwrap it from the cheesecloth and gently shape it into a ball with your hands. Gently press the 1/3 C finely chopped pistachios around it and serve immediately.
You can also add the pistachios a couple hours before serving and leave the cheeseball in the fridge on your serving platter. Then it’s all ready to go when your guests arrive.