Turn on the IP to 'Saute' mode. Add the butter, followed by the garlic and onions. Sauté for a few minutes till the onions turn translucent.
Next, add the cubed butternut squash and stir it with the rest of the ingredients.
Add the vegetable broth or water, salt and mix well.
Meanwhile, in an oven-safe bowl or stackable steamer, insert pans add 3 cups of pasta with 3 cups of water, and keep aside. Make sure pasta should be submerged in liquid.
Then place the trivet and then the bowl of dried pasta with water. This way, they will both cook together. See pictures below for reference.
Close the lid of the Instant Pot. Set the cooking time for 4 minutes (or half the time on the macaroni cooking directions minus 1 minute).
Once the IP beeps, do a QUICK RELEASE.
Open the lid and, using an immersion blender, puree squash with some milk till smooth and creamy. OR you can also puree the squash in a regular blender or Vitamix.
Now add the cooked pasta followed by cheese, seasoning, salt, pepper powder. Stir constantly until cheese is melted and everything is combined.
Serve pasta topped with more Parmesan cheese and parsley.