Slice the spam into bite-sized pieces, then julienne the onion and scallions. Set aside.
Wash rice twice, then fill it up with water again to soak for a couple of minutes, then set aside the water in which the rice is soaked. You can cook the washed rice after.
Place a small pot on high heat, then put sesame oil, spam, and kimchi in it. Let it cook without mixing.
Add rice water to the spam and kimchi, then let it simmer. Once boiling, add onion and scallions.
Season with garlic, black pepper, hondashi, and doenjang, mix gently, then taste and adjust with soy sauce, pepper powder, or pepper flakes.
Add the tofu last, then leave it to boil until the spam is tender, the kimchi and aromatics are a bit wilted, and the soup is flavorful and thickened.