Switch on the Instant Pot and select the sauté setting.
Add the olive oil, diced onions, sliced celery and diced carrots and sauté until the veggies start to soften - around 5 to 10 minutes.
In the meantime, rinse the beans and set them aside.
Once the veggie are soft, add the minced garlic and tomato paste (puree) then cook and stir for a further minute. Season generously with sea salt and black pepper.
Add the diced cooked ham, rinsed beans, chicken broth, thyme sprigs, bay leaf and red pepper flakes. Taste and check for seasoning, adjust if needed.
If you are using a ham bone, add this to the pot now too.
Stir, close and latch the lid. Turn the valve to “SEAL” and set the Instant Pot to pressure cook on high pressure cook mode for 40 minutes.
Once the program has finished, allow it to natural release for about 10 minutes and then do a quick release. Be careful opening the lid as the steam will be hot.
Check and adjust seasonings to taste, remove the ham bone if using and serve sprinkled with fresh chopped parsley.