Add oil to the instant pot and turn to saute. Add carrots, onions and celery to the pot and saute for 2 minutes. Add diced tomatoes, tomato paste, chicken broth, oregano, and basil and stir to combine.

Turn Instant pot off. Secure instant pot lid and set the valve to “sealing”.

Cook on Manual/High Pressure for 5 minutes. When the timer beeps allow the pressure to naturally release for 5 minutes.

Meanwhile, make the roux. Add butter to a large saucepan over medium-low heat. Once butter has melted, stir in the flour.

Cook, stirring constantly for about 10 minutes or until the roux is a nice golden brown color.

Pour the soup from the instant pot into a blender and blend until smooth (please do this in 2-3 batches, depending on how big your blender is).

Add one cup of the pureed soup from the instant pot to the roux and stir to combine. The mixture will start to form a thick paste. Slowly add another 3 cups of soup to the roux. Add the roux mixture back to the instant pot and stir until smooth.

Stir in the Parmesan cheese, half and half and salt and pepper. Tastes and add additional oregano and basil if desired, to taste.