Heat the sesame oil in a large soup pot over medium heat. Add the pork belly, season with salt and pepper, and cook, stirring now and then, until rendered, browned, and crispy, about 10 minutes.
Add the onion and kimchi and stir to combine. Add enough water to nearly cover the pork mixture (5 or 6 cups), cover, and bring to a boil. Immediately reduce the heat and simmer until the onion and kimchi are softened and the soup is quite thick, about 20 minutes.
Stir in the fish sauce (or dashida), American cheese (if using), and scallions. If it's too thick for your liking, thin the stew with water. Cover the pot and simmer for 10 minutes to combine the flavors. Serve steaming hot sprinkled with gim.
Note: Gim is pressed and toasted sheets of laver seaweed. Japanese nori makes a good substitute.
Photograph by Andre Baranowski.
Reprinted from: The Kimchi Chronicles (c) 2011 by Marja Vongerichten. Permission granted by Rodale, Inc. Available wherever books are sold.