For the cheese ball, place cashews and pistachios in a bowl and cover with boiling water; soak for 15 minutes, then drain water and place nuts in a blender. Add water, coconut oil, nutritional yeast, tapioca starch, apple cider vinegar, salt, and onion powder to the pitcher. Puree until smooth, let sit for 3 minutes, then blender again until very smooth. Add rosemary to mixture and pulse until it is broken up into small pieces.
Transfer mixture to a sauce pan, warmed over medium heat, whisking often. After the starch is activated (once simmering starts), the "cheese" will become goopy and stretchy. Stir it until you're able to form a loose ball in the pan, then take it off heat.
For the crust, place pistachios, rosemary, and pepper in a bowl, mixing until evenly combined. Then, have ready a small bowl, lined with plastic wrap or cheesecloth, to the side. Transfer cheese ball to the nut-mix bowl and roll it around to coat the outside evenly (the ball is still pretty soft at this point). Sprinkle leftover nuts into lined bowl, then place cheese ball on top, covering top with the wrap/cloth, twisting it and tieing to shape it into a sphere. Chill ball in freezer for roughly two hours, then serve with 8 ounces (225 g) or more crackers.