Start the instant pot in Saute mode and heat oil in it. Add diced onions, ginger and garlic and sauté for about 3 minutes.
Add butternut squash, red curry paste, broth and stir to combine. Press Cancel and close lid with vent in sealing. Change the instant pot setting to manual or pressure cook mode at high pressure for 8 mins. Pressure release naturally for 10 minutes.
Use an immersion blender to blend the soup to a creamy texture. You can also transfer to a blender such as Vitamix to blend the soup. Be careful while blending to avoid hot splatters.
Add coconut milk, lime juice and stir well. Add salt, pepper and chili flakes to taste.
Garnish the soup with cilantro, coconut milk and peanuts. Serve hot with a side of crusty bread!