Put all spices into a small bowl, mix well.
Cut the pork into 3-4 inch pieces, trim off the excess fat. Then add in the spices and rub the pork on all sides until all covered. Cover with plastic and put it in the refrigerator for 3 hours or more.
After 3 hours, take out the pork from the refrigerator and let it relax for 15 mins.
In a small bowl, pour in the sauce ingredients and stir well. Make adjustment to your personal taste.
Add olive oil into the pressure cooker, turn it on pan-fry/saute mode. Place the pork in the pot and brown on all sides. (You may take out the garlic or onions before they get burned.
Turn off pan-fry/saute mode, pour in the sauce. Closed the lid.
Press ‘Meat’ button or set to high pressure for 45 mins. Natural release.
When the green light is on. open the lid. Transfer the pork to a large bowl.
Transfer the sauce from pressure cooker to a small pot. Use high heat to boil the sauce until thickened. It takes about 20-25mins, and stir occasionally. Meanwhile, use two forks to shred the pork into slices.
Add two spoons of the sauce to the pork, gently mix well.
Cut the burger buns into halves, toast them the both sides in a frying pan.
Place the meat on the buns, serve sauce on side.