1. Add water to the kombu and boil it in a pot. After the water boils, continue to boil it on a low fire.
2. After cutting the onions, remove the kelp and cut into small pieces, and add a small amount of Japanese soy sauce to the water.
3. Pour the onion and kelp back into the pot and continue to cook for 10 minutes.
4. The fat beef is scalded with boiling water to remove the blood and a part of the fat (personal preference), then pour it into the pot, wait until the beef is completely discolored, and then cook for 3 minutes. Season with a little salt.
