Prepare the Instant Pot: Set your Instant Pot to the Sauté function and add olive oil. Allow it to heat until shimmering but not smoking.
Sauté the aromatics: Add the chopped onion and cook for 3-4 minutes until translucent. Add garlic and cook for another 30 seconds until fragrant, stirring constantly to prevent burning.
Add remaining ingredients: Add the butternut squash cubes, carrots, dried sage, nutmeg, cinnamon, salt, and pepper. Stir to coat the vegetables with the spices.
Pour in the broth: Add the vegetable or chicken broth, making sure all ingredients are submerged. If needed, add a bit more broth or water.
Pressure cook: Secure the Instant Pot lid and set the valve to “Sealing.” Cook on High Pressure for 8 minutes, then allow a natural release for 5 minutes before carefully performing a quick release.
Blend until smooth: Using an immersion blender, purée the soup directly in the pot until completely smooth. Alternatively, transfer in batches to a regular blender (being careful with the hot liquid).
Finish with cream: Return the soup to the Instant Pot if you used a regular blender. Stir in the heavy cream or coconut milk and adjust seasoning to taste.
Serve warm: Ladle into bowls and garnish as desired with a swirl of cream, roasted pumpkin seeds, or crispy sage leaves.