Prepare the napa cabbage. Chop off the base, separate the leaves, and rinse with water to clean.

Bring water to a boil in a pot. Blanch the napa cabbage leaves in boiling water for 10 seconds. Remember, blanching should only be done for a few seconds and not longer than 10. Otherwise, the leaves will wilt and become too soggy for folding.

Remove and cool the leaves in a bowl of water. Drain out the excess water by gently squeezing the leaves. Cooling the leaves in water will stop them from further cooking, preventing them from going too soggy.

In a large bowl, mix minced meat with chopped green onions, diced ginger, salt, chicken bouillon powder, white pepper, an egg, and cornstarch. Stir well.

Fold the rolls. Place the meat mixture at the bottom, on the white base of the napa cabbage leaf. Roll the leaf starting from the white base and going to the green part on top. Bring the left and right ends together by folding them downwards to the middle of the roll. The folded part should be facing the bottom to lock it and prevent it from opening as it steams. If you want to make the rolls more attractive, you can tie the folded rolls with long thin carrot strips to serve as a ribbon.

Bring a pot of water to a boil. Place the rolls on a serving plate in a steamer basket. Steam in a steamer for 8 minutes.

After steaming, water should be pooled at the steamer's base. Use this steamed soup and transfer it to a pot to serve as the sauce base.

Add 50g of water, salt, chicken bouillon powder, and light soy sauce.

Thicken the sauce with cornstarch slurry (2 teaspoons of cornstarch mixed with 3 teaspoons of water). Add diced red and green bell peppers. Simmer until the sauce thickens.

Pour the sauce over the steamed cabbage.