Prepare your vegetables and add them to the IP insert with the oil.
Press the "Saute" button and saute until the onions become translucent.
Pour in the remaining ingredients and stir.
Turn off the IP, then press the "Manual" button and adjust time to 40 minutes.
Allow a 20 minute natural release, then open the valve an allow any remaining steam to release before opening the lid.
If you are using the arrowroot or cornstarch to thicken, whisk it in quickly while the soup is still hot, being sure to whisk out any clumps. Allow soup to sit for 10 minutes or so, stir and serve.
Serve with a slice of crusty garlic bread.
Notes
Please note that the nutrition data given here is a ballpark figure. Exact data is not possible.