Press the sauté button on the Instant Pot, and add the oil, onions, celery, carrots and garlic to the pot. Stir-fry for 5 minutes. (This is an optional step. You can dump everything in at once if you want).

Add the remaining ingredients to the pot.

Secure the lid, close the pressure valve and cook for 35 minutes at high pressure.

Allow the pressure to release naturally.

Remove the ham bone from the pot. Once cool enough to handle, remove the meat from the bone and put it back in the pot.

Serve the soup with fried pieces of chopped ham (make sure you do this! It takes the soup to another level!).

Add everything to the slow cooker and cook on low for 8 hours.

Serve the soup with fried pieces of chopped ham (make sure you do this! It takes the soup to another level!).