Begin by preparing butternut squash. Cut the top off of the squash and then cut it in half, length-wise. Use a large spoon to remove the seeds and discard them. Then, cut each half in half again, length-wise to quarter the squash.
Next, turn on the Instant Pot's saute feature. Add olive oil.
When olive oil is fragrant, add onions and garlic to the Instant Pot and saute for 7-9 minutes, stirring periodically.
Then, deglaze your Instant Pot by adding broth. Use a wooden utensil to scrape the brown bits from the bottom of your pot. This will help prevent the burn notice.
Set the quartered squash on top of the onions, garlic, and broth. Season the squash with salt, pepper, and cinnamon. Pour apple cider vinegar over the squash.
Close your Instant Pot and turn the valve to seal. Cook on high pressure for 8 minutes. It will take around 10 minutes for the pressure to fully build up and start counting down from 8.
When the timer goes off, quick-release the pressure and uncover the Instant Pot.
Remove quartered butternut squash from the Instant Pot and carefully scoop the innards out from the butternut squash skin. Be careful, it will be hot! Discard the skin, and place innards back into the Instant Pot.
Use an immersion blender to blend everything together until smooth.* Option to add a little more broth if you like your squash soup thinner.
Serve, and enjoy!