Put the peas in a strainer and rinse thoroughly with water. Set aside.
Set the Instant Pot to sauté. Melt the bacon fat or butter, and then add onion, garlic, celery, carrots, and jalapeño. Sauté until soft, about three minutes.
Add the chicken stock, ham hock, thyme, rosemary, salt, and pepper. Stir to combine. Put the lid on the Instant Pot and set to cook at high pressure for 15 minutes. Manually release the pressure.
Add the peas and stir. Replace the lid, set to high pressure (with the “keep warm” setting on) for 15 minutes for dried peas and 8 minutes for presoaked. Allow pressure to naturally release for 10 minutes and then manually release.
Use tongs to remove the ham hock to a cutting board. Remove thyme and rosemary stems as well. When the ham is cool enough to handle, remove the meat from the bone and chop into bite-size pieces. Add them back into the pot.
Add apple cider vinegar, and additional salt and pepper to taste.
Serve with collards, rice, and/or cornbread, and the hot sauce of your choice.