Wash the Napa cabbage; remove the green leaves. Cut the white part into pieces around 1/2 inch long.
Minced garlic, ginger, white part of green onions, and red pepper. In a small bowl, mix vinegar, water, sugar, starch, soy sauce and sesame oil. Set aside.
In a large pan or wok, heat up oil and fry ginger, garlic and green onion white parts until aroma. Add doubanjiang and continue frying for around 1 minute over medium fire until there is red oil coming out.
Place the Napa cabbage pieces. Cook until slightly soft (around 1 to 2 minutes). Swirl the sauce and bring to a boiling. Taste to see whether pinch of salt is desired.
Transfer out and top with chopped green onions. Serve hot with steamed rice.