Press the "Sauté" button on the Instant Pot and wait for it to heat up. Add the olive oil and diced onions with a pinch of salt. Cook, stirring occasionally, for about 3 minutes until the onions are softened and transparent.
Add the carrots, celery, garlic and cook for another 3 minutes.
Add the chopped tomatoes and stir well. Pour in the water or vegetable broth, then add the diced potatoes, salt and Italian seasoning. Stir to combine.
Close the lid of the Instant Pot and set the valve to the sealing position. Cook on high pressure for 8 minutes.
Once the cooking cycle is complete, allow the pressure to release naturally for 10 minutes, then manually release any remaining pressure.
Open the lid carefully and stir in the cannellini beans. Close the lid again and let the residual heat heat through the beans for about 2 to 3 minutes.
Stir in the spinach until wilted and remove the bay leaves.
Taste and adjust the seasoning if needed. Serve hot.
Notes
Pressure Cook: Make sure the Instant Pot is set to high pressure and the valve is in the “sealed” position. This ensures even and quicker cooking of your soup.
Natural Release: Allow pressure to release naturally for 10 minutes before manually releasing any remaining pressure to prevent splattering.
Vegetable broth: If using salted vegetable stock, make sure to halve the salt on your recipe and adjust if needed after cooking.