Place the metal trivet in in your Instant Pot with the handles side up. Add in the water.
Place the spaghetti squash cut side up on the trivet. Close the lid and seal the valve.
Cook on high pressure for 7 minutes. Manually release the pressure.
Remove the spaghetti squash from the Instant Pot and set aside. Pour out the water and wipe the Instant Pot dry.
Set the Instant Pot to "saute" and add in the butter and oil. Once the butter is melted, add in the garlic, pepper and red pepper flakes. Cook for around 2 minutes.
Turn off the Instant Pot. Using a fork, remove the spaghetti squash strands into the Instant Pot. Mix in the Parmesan cheese and dried parsley. Serve immediately.