Select the "saute" function on Instant Pot. Add the olive oil, onions and carrots, and cook for 2-3 minutes, until the onions become translucent.
Turn off the saute. Add in the canned tomatoes, vegetable broth, dried basil and salt. Lock the lid and close the pressure valve to seal. Cook on high pressure for 5 minutes.
Once it beeps, allow the pressure to naturally release.
While the soup is cooking, prepare the cashew cream. Soak the cashews in hot water for 5 minutes, then drain and add to a blender with the 3/4 cup water. Blend until very smooth. Set aside.
Remove the lid from Instant Pot. Using an immersion blender, blend until the soup is very smooth. You may also blend it all in a regular blender if desired.
Taste and adjust, adding more salt if desired, or 1-2 teaspoons sugar to cut down on any acidity.
Now stir in the cashew cream. You may not use it all, depending on how creamy you want the soup. Or, add a few tablespoons of the cream directly to bowls of soup when serving.
Top with optional fresh basil, and serve.
In a large soup pot, saute the onions and carrots in the olive oil for a couple of minutes. Add the tomatoes, vegetable broth, dried basil and salt. Simmer for 8-10 minutes. Blend, add cashew cream and serve.