Add olive oil to inner pot of Instant Pot and select saute mode
When oil is heated, add onion, garlic and italian sausage to pot. Cook until sausage is no longer pink, and crumbled.
Drain excess fat from pot.
Add rest of the ingredients, minus cream cheese and garnishes, to the inner pot of the Instant Pot and stir well. Replace and lock lid and turn valve to sealed position.
Select soup setting, normal pressure, and cook for 10 minutes. It will take the pot 10-15 minutes to reach pressure before cooking time starts.
When finished cooking, let natural release for 10 minutes, then release the rest of the pressure by flipping valve to venting.
Leave pot on keep warm mode and remove lid. Stir in cubed cream cheese until melted and incorporated into pizza soup. Turn off Instant Pot.
Serve warm, garnish with mozzarella cheese and extra pepperonis if desired.
Notes
Making in the Slow Cooker?
Follow the same instructions for browning the sausage, but do so on the stove top. Drain excess fat.
Add all ingredients minus the cream cheese and garnishes to the pot of the Slow Cooker.
Place lid on top and cook for 6-8 hours on low or 3-4 hours on high.
30 minutes before serving, add cubed cream cheese to pot and allow to melt. Stir to incorporate.
Serve warm with cheese and extra pepperoni for garnish.