Clean the flounder thoroughly and cut it into large pieces.
Slice the radish, onion, and green onion to prepare.
Place the sliced radish at the bottom of a pot, then add the flounder pieces, onion, and green onion on top.
Mix soy sauce, red chili powder, minced garlic, ginger, sugar, pepper, and water to make the sauce.
Pour the sauce into the pot and bring to a boil over high heat.
Once it starts boiling, reduce to medium heat and simmer until the broth is reduced.
Finally, add Cheongyang chili peppers and simmer for a little longer.