Heat the Instant Pot using the saute function and add olive oil.
When the oil is hot add the onion, carrot, and celery.
Saute, stirring occasionally, until the onions are just starting to soften, about 5 minutes.
Add the minced garlic, broccoli, and chicken stock. Stir to combine.
Attach the lid and ensure the valve is in the sealing position.
Pressure cook on manual high for 2 minutes.
Once the Instant Pot has finished cooking, release the pressure manually by switching the valve into the venting position. Be careful this will release hot steam.
In a small bowl stir together the grated cheese, flour, and cornstarch.
Remove the lid of the Instant Pot and switch to the saute function.
Add the cheese, a little at a time, stirring occasionally.
Once all the cheese has been incorporated, add the heavy cream and cook the soup for 2-3 minutes or until the soup has thickened slightly.
Enjoy immediately and if desired top with additional cheese.