Instant Pot Cheesy Spaghetti Squash

Place trivet in Instant Pot and pour in water. Season spaghetti squash halves with salt and pepper and place  in Instant Pot and lock lid. Set to Pressure Cook on High for 7 minutes. Follow manufacturer's guide for quick release, then unlock lid.  Remove squash and let cool until cool enough to handle.  Preheat oven to broil. Using a fork, scrape spaghetti squash strands into a large bowl, reserving squash skins. Add spinach, ricotta, oregano, and red pepper flakes and toss to combine. Place mixture back into squash skins and top with marinara, mozzarella, and Parmesan. Place squash on a large baking sheet and broil until cheese is melty, 5 minutes. Garnish with parsley to serve.