Blend the base: Add ¾ cup shelled pistachios, milk, heavy cream, sugar, and vanilla extract to a high-speed blender. Blend until completely smooth and creamy.
Freeze the mixture: Pour the mixture into a clean Ninja Creami pint container. Do not exceed the MAX FILL line. Place on a flat surface and freeze for 24 hours.
Spin it: Remove the pint from the freezer. Let it sit at room temperature for 5 minutes. Place the pint in the outer bowl, attach the lid, and lock it into the motor base. Press the ICE CREAM button.
Re-spin if needed: If the texture is dry and crumbly, add 1 tablespoon of milk or cream and press RE-SPIN.
Add mix-ins (optional): Once the texture is creamy, use a spoon to make a hole in the center and add the remaining ¼ cup of chopped pistachios or other mix-ins. Press the MIX-IN button to combine.
Serve: Serve immediately and enjoy!
