Turn instant pot on to sauté setting. Add olive oil to pot. Saute onion, celery and garlic for 4-5 minutes until fragrant. Add curry paste and stir. Cook for an additional minute.
Press cancel and then turn on the pressure cooker setting.
Add butternut squash and broth.
Lock lid in place and put instant pot on soup setting (it should cook for about 30 minutes or so on high pressure).
Once done, allow the pressure to naturally release. If in a rush, you can also do quick release following the instructions in the manual (or refer to tips above).
Open lid, using an immersion blender, blend until smooth. You can also transfer to a regular blender and blend the soup in batches.
Add coconut milk and blend again.
Season with salt and pepper to taste. Serve topped with roasted pumpkin seeds or see other serving suggestions above!