IF using raw onion rather than onion flakes – turn on the IP and select Sauté. Once hot add oil to the pot. Add onion, and cook for a 2-3 minutes, stirring frequently.
Add water and using a wooden spoon scrape well the bottom of the IP to remove any bits that stuck to it, make sure you scrape it well to avoid burning during cooking. Add remaining ingredients to the IP. Stir to mix well.
Close lid and seal valve. Set high pressure and cook for 10 minutes. Natural release pressure for 5 minutes then manually the remaining pressure.
Blend in food processor or immersion blender until smooth.