First, please read your Instant Pot instructions if you are still unfamiliar with how your Instant Pot works.
Prepare your apples. Cut out the core and all the seeds, then slice your apples into 6-8 slices each. The slices can be pretty large. Do not peel the apples.
Add the apple slices, water, cinnamon, vanilla extract, and apple cider vinegar to your Instant Pot and mix everything together. Secure the lid, ensure the vent is sealed, then set your Instant Pot to pressure cook on high for 10 minutes. It will take around 15 minutes to pressurize, then the 10 minute timer will start.
When the 10 minutes are done, leave your Instant Pot so it can do a natural release for 15 minutes, then carefully do a manual release with an oven mitt on until all pressure has been released. Do not attempt to remove the lid before the pressure has been released.
The contents of the Instant Pot will be very hot. Allow them to cool a bit, then transfer about half the contents of the Instant Pot to a blender. Blend until completely smooth, then pour the mixture into a large pot. I blend in two stages because everything at once would be too much for my blender. The apple mixture will still be hot, so make sure you pause during blending to release hot air.
Once everything is blended completely, mix it all together in one large pot. Heat on the stovetop on low-medium heat to thicken this mixture into apple butter. Let it heat for 1 -2 hours, stirring as much as you can. It’s okay to leave it and come back to it to stir a bit every 10-15 minutes or so. However, make sure that you leave a lid on it when you are not stirring, because it will splash up and make a mess. The lid mush have an air vent. Slowly lift the lid when you are stirring, and make sure you wear an oven mitt in case the mixture splashes up onto your hand. It will be hot! When you lift the lid, try to avoid letting the condensation drip back into the pot.
Keep doing this until the apple butter has reached your desired thickness. I like to heat it for 1.5 hours.
Once the apple butter has cooled completely, scoop it into jars and store it in the fridge or freezer.
Once in the fridge, this apple butter should keep for at least 3 weeks. When you need more, just transfer a jar from the freezer to the fridge.