Cut the beef, onion, and Cheongyang green chili pepper into bite-sized pieces.
Add cooking oil to a pot and stir-fry the beef and onion.
When the beef is about half-cooked, add the Cheongyang chili pepper and minced garlic, then stir-fry together.
Add gochujang (Korean chili paste) and gochugaru (Korean chili powder), and mix well until dissolved.
Pour in the broth and bring to a boil.
Add tofu and green onion, let it simmer briefly, and finish the soup.