Place onion and garlic into the Thermomix bowl and chop 3 sec/speed 8. Scrape out and set aside.
Peel and core pineapple. Cut half of the pineapple into bite sized pieces and set aside. Place the other half into the Thermomix bowl and chop 5 sec/speed 7 Cook 15 min/80°C/speed 1. Puree 10 sec/speed 10.
Meanwhile, heat a good dash of EVOO in a cast iron pot with a lid to a high heat. Season the pork well with salt and pepper and brown the pork in the hot oil in batches until well browned on all sides. This will take at least 8 minutes per batch.
Add the chopped onion and garlic mixture to the pork and keep cooking, stirring occasionally until fragrant and softened. Add a little more oil if needed.
Add the cooked pineapple puree, vinegar, soy sauce, oyster sauce, sugar, peppercorns and bay leaves. Cover and reduce heat to a slow simmer. Cook pork until very tender, around 45 minutes.
Heat more oil in a seperate frying pan and caramelise the remaining chopped pineapple pieces until golden on all sides. Transfer into the cooked pork mixture and stir gently to combine.
With the pot uncovered, cook the pork a further 10-15 minutes or until the sauce is thickened and glossy.
Serve over steamed rice with plenty of sliced spring onions on top.