Turn pressure cooker to brown/saute function.
Add the Italian sausage and cook until browned, breaking it up into smaller pieces as it cooks.
Add the onion, celery, and carrots and cook for another 5 minutes, until slightly softened.
Add the minced garlic, dried herbs, and salt, stirring well to incorporate.
Add the chicken broth, and stir to combine.
Place the lid on the pressure cooker, close the pressure valve, and cook on HIGH pressure for 6 minutes.
Carefully release the pressure from the Instant Pot.
Turn the saute/brown function back onto the Instant Pot.
In a bowl, whisk together ½ cup of the half and half with the cornstarch. Add to the soup. Slowly stir in the remaining 1 cup of the half and half. (The purpose of doing this is to make sure the cornstarch does not clump in the half and half and it's best to add it to a smaller amount of liquid)
Add the gnocchi and spinach.
Let the soup simmer for 5 minutes, until slightly thickened and gnocchi is softened.
Stir in Parmesan cheese.
Serve and enjoy!