Press the Sauté button on the Instant Pot® and heat the coconut oil. Add the onion and carrots. Sauté for 3–5 minutes until onions are translucent. Add the garlic and curry paste. Continue to sauté for 1 minute. Add remaining ingredients, except 3 tablespoons basil. Lock lid.
Press the Soup button and adjust time to 20 minutes.
When timer beeps, let pressure release naturally for 10 minutes. Quick-release any additional pressure until float valve drops and then unlock lid.
In the Instant Pot®, purée soup with an immersion blender, or use a stand blender and purée in batches.
Ladle into bowls, garnish each bowl with 1/2 tablespoon basil, and serve warm.