In a large bowl, mix together the pineapple juice, soy sauce, and brown sugar.
Add in the cubed pork shoulder. Marinate for 3-4 hours. Overnight is even better.
Once the pork is finished marinating, strain the pork of the marinade in a colander. Pat dry.
Save all of the marinade.
Heat up the cooking oil in a dutch oven over medium high heat. sear the pork shoulder in batches, making sure to not overcrowd the dutch oven. Add each batch of the seared pork shoulder back into the marinade.
In the same dutch oven, sauté the onions and garlic for 3-4 minutes.
Stir in the 2 cups of chunked pineapple. Sauté for 5 minutes.
Stir in the green onions.
Add in the pork shoulder with all of the marinade and 1 cup of beef stock. Simmer for 60 minutes.
After simmering for an hour, the juices of the pork hamonado will reduce down drastically. The sauce should look like a thick brown gravy.
Serve with steamed jasmine rice.