Wash the napa cabbage thoroughly and cut it into bite-sized pieces.
In a bowl, mix soy sauce, minced garlic, sugar, sesame oil, and chili powder to make the seasoning sauce.
Evenly coat the cabbage with the sauce.
Pour water into a steamer, place the cabbage on top, and steam for 10-15 minutes.
Transfer the steamed napa cabbage to a plate and sprinkle with sesame seeds to finish.