Press the saute button on your Instant Pot and place the oil in the bottom.
Once heated, add in the onions. If adding bacon or mushrooms, cook it now with the onions.
Fry until soft and translucent, then add in the garlic, carrots and celery and fry for another 2-3 minutes.
Add in the broth, the ham bone (if using), split peas, bay leaves and thyme. Add in any other meat, vegetable or spice additions now.
Place the lid on the Instant Pot and close and seal according to the manufacturer's instructions.
Cook on high pressure for 20 minutes. Once done, let the soup sit and naturally release for 20 minutes, then remove the lid according to the manufacturer's instructions.
Remove the ham bone and chop off any meat, returning the ham to the pot.
Stir and serve while warm.
Nutrition is an automatic estimate and will vary with the brands you use.
Recipe from https://fastandslowcooking.com/instant-pot-split-pea-soup/