Press saute on your pressure cooker.
When hot, add oil, onion, carrots, celery and saute for a few minutes.
Add the minced garlic and continue to cook until fragrant, about a minute.
Pour in the broth, or water.
Add the rinsed beans, ham shank or ham hock, and seasonings.
Close the lid and make sure the valve is closed.
Cook on high pressure for 45 minutes and allow to naturally release pressure for 15 minutes.
Release any remaining pressure and open the lid.
Carefully remove the ham to a cutting board and chop into pieces, removing any bones or skin.
Return the chopped ham to the pot and stir.
Serve hot and top with green onions if desired.