Cut the top off of the pumpkin and remove the seeds and pulp. Set the seeds aside to roast, if desired. Place the pumpkin on the trivet and lock the lid.
Press the pressure cook button and set the time to 7 minutes. When the time is up, do a 5 min natural release before releasing the remaining pressure.
For pumpkin puree
Place the whole pumpkin (no need to cut off the stem or dig out the seeds) onto the trivet and lock the lid.
Press the pressure cook button and set the time to 12 minutes. When the time is up, do a 5 min natural release before releasing the remaining pressure.
Remove the pumpkin from the Instant Pot and allow it to cool slightly before scooping out the flesh.
Notes
If you are using the pumpkin as a bowl, choose a serving-size pumpkin.
If you are using the pumpkin for puree, you can use a larger pumpkin, as long as it fits inside the Instant Pot. The skin of the pumpkin will pull free of the outside as it cooks and the insides easily scoop out with a spoon.
The pumpkin puree will keep for up to 5 days. If you don't use it by then, you can freeze it for 3-4 months.