Prepare the pork belly, garlic, onion, scallions, and jalapeño.
On high heat, cook pork belly until crispy and lightly brown.
Remove the pork belly from the pan and set aside, then fry the garlic in the pork fat until crispy and light brown. Set the garlic aside.
Remove the pork fat from the pan with a paper towel and put back the pork belly back into the pan.
Add the chopped onions and scallions to the pan, saute it all together until fragrant.
Meanwhile, combine soybean paste, garlic, soju, sugar, oyster sauce, and water. Mix thoroughly.
Add the sauce to the pan. Simmer until water reduces, and the pork belly is thoroughly cooked.
Transfer to a plate and garnish with fried garlic, scallions, jalapeño peppers, sesame seeds, and sesame oil.