Note: You don’t need to be precise with cutting your vegetables. The soup is going to be blended.
Press the saute’ button and set to “normal”. Let the Instant Pot heat up. This will just take a few minutes. When hot, add the butter and let it melt. Now, add your onions, carrots and celery and saute’ just for just 3 minutes. The veggies soften just a bit.
It’s now time to add your can of whole tomatoes, your can of tomato sauce, your chicken broth, sugar, salt, and black pepper. Give this all a stir. Hit cancel on your Instant Pot. Close and seal your lid. Press the pressure cook button and you want it set to “manual high” and set for 6 minutes. Close the lid and seal.
When the time is up, press the cancel button and quick release using by pressing down the vent button. Wait till all the pressure has released and the pressure pin has dropped. It's now safe to open the pot.
Press the saute’ button and click till it says “more”. This is just getting you to a higher saute’ temperature. Now, it’s time to finish this delicious soup. Stir in your milk and then blend using an immersion blender till the soup is nice and smooth. Let it cook for 4-5 minutes until all the flavors have married together. This soup is so good that you will never want to buy canned soup again!
Note: if you don’t have an immersion blender, you can blend this in a few batches in a regular blender and return to the Instant Pot to finish.