Press the sauté button, add oil and allow it a minute to heat up. Add the cumin and mustard seeds. Once the cumin seeds brown and the mustard seeds begin to pop, add the onions and Serrano pepper. Stir-fry for 8-10 minutes, or until the onions begin to brown.
Add the pork, garlic and ginger. Stir for 3-4 minutes to brown the meat on all sides.
Add the spices, give everything a good mix, then add the vinegar and water.
Secure the lid, close the pressure valve and cook for 25 minutes at high pressure.
Naturally release pressure.
Open lid, press the sauté button and cook for 8-10 minutes to boil off some of the liquid and reduce the gravy to a stew like consistency.
Garnish with cilantro and serve.