Clean, peel and chop the butternut squash into cubes. Chop the onion, garlic, and carrots.
Set the Instant Pot to SAUTE and add 2 tbsp butter. Once the butter has melted, add the onions and cook for 5 minutes. Add the chopped garlic and cook for an additional minute, stirring often so the garlic doesn't burn.
Pour in 1 cup stock and use your spoon to scrape off the brown bits off the bottom of the pot. This will enhance the flavor of the soup and make clean-up easier.
Add the squash, carrots, additional stock, cayenne pepper, cinnamon, nutmeg, sage, oregano, salt, and pepper. Secure the lid on the Instant Pot and close the steam valve. Set the Instant Pot to pressure cook HIGH for 10 minutes. After the cycle is complete, allow the steam to naturally release for 10 minutes and then manually release the rest.
In batches, carefully add the ingredients to a blender and blend until smooth. Be careful, the ingredients are HOT! Alternatively, you can use an immersion hand blender right in the Instant Pot.
Return the soup to the Instant Pot and stir in the heavy cream. Taste for any seasoning needs and add additional salt or pepper if needed. Serve with optional garnishes.