Saute kimchi. In a large pot, add 1 tsp sesame oil + 1 tsp vegetable oil. Add kimchi and cook on medium heat until soft, caramelized, and the liquid is mostly evaporated, about 10-15 minutes.
Add pork belly, pork bones (if using), water, and gochujang. Cover and bring to a boil. Lower heat and simmer until pork belly is jiggly and tender, pork riblets/ribs are falling off the bone, and the kimchi is cooked braised and soft, about 25-30 minutes.
Add tofu. Cube tofu and add to the pot. Cover and simmer until heated through, about 5 minutes.
Taste Kimchi Jjigae. If it tastes flat, add a dash or two of fish sauce and mix. If it's too acidic, add a pinch of sugar. If it tastes too raw, cook 10-15 minutes longer.
Add sesame oil and butter. Add drizzle of sesame oil and butter. Garnish with green onion and sesame seeds.
Serve and enjoy. Ladle into bowls and serve with rice. *If using leftover pork chop bones, don't forget to remove them before serving. Pork ribs and riblets can be served, as is.
