First, you need to make a mayonnaise. To do that, add the coconut oil, avocado oil, apple cider vinegar and egg yolks to a tall and narrow container that's barely wide enough to accommodate the head of your stick blender. Let that sit for a few seconds, just long enough for the egg yolks to settle comfortably at the bottom of the jar, underneath the oil.
Insert your immersion blender and push it all the way down until it makes contact with the bottom of the jar, then push the power button and do not move the blender for a full 20 seconds. As the oil starts to emulsify, start moving your blender around and up and down just to make sure that every last bit of oil gets well incorporated. You should now be staring at a beautiful, creamy mayonnaise. Set it aside.
Add the coconut milk, gelatin, matcha powder, vanilla, cinnamon and salt to a large container, preferably one with a pouring spout. Blend well with your immersion blender, until completely smooth.
Add the reserved mayonnaise and the flesh of the avocados then blend again until smooth and perfectly combined.
Transfer this mixture to your ice cream maker and churn according to the manufacturer’s instructions. When the ice cream is almost set, throw in the chopped pistachios and continue churning until the nuts are evenly distributed.
You can serve this ice cream immediately as a soft serve or transfer it to an airtight container and place it in the freezer for a couple of hours to firm up. If you leave it in the freezer for longer than that, it will become rock solid, so you will need to take it out of the freezer and place it in the refrigerator for 6-8 hours prior to serving.