Sauté the onions and mushrooms (optional) in olive oil.
Combine the ground pork and beef with the onions and mushrooms, Korean BBQ sauce, breadcrumbs, salt and pepper into a large mixing bowl. Use your hands to combine the ingredients.
Next, use a large cookie scoop to make meatballs the same size and roll them gentle into balls. Do not overwork the meat mixture or the Korean meatballs will become tough.
When all the meatballs are ready, twist on the locking lid and set the valve to SEALING.
Select the MANUAL mode, HIGH PRESSURE for 7 minutes.
After the pressurized cook time has ended, allow the Instant Pot to NATURAL PRESSURE RELEASE for an additional 7 minutes.*
Carefully release any remaining pressure and take off the lid.