Mix together the maple syrup, melted butter, cinnamon, nutmeg, vanilla and salt and pour over the apples and toss until the apples are evenly coated.
Pour the apple juice into the Instant Pot and add the apples.
Seal the IP and pressure cook for 2 minutes (it will take 12-13 minutes to come to pressure). Allow for a 5-minute natural release and then do a manual/quick release, which should take just 1-2 minutes.
Remove the lid and turn the IP off. Use a potato masher and mash the cooked apples. (If you like a smoother texture you could blend the apples with an immersion blender or pulse the mixture in a food processor or a standing blender.)
Enjoy warm or cold. Store in the fridge for up to 7-10 days.