||Cut the cabbage leaves in half, removing the tough center seams. Bring the water to a boil and drop in the cabbage leaves. Remove from the boiling water after 3 minutes and set aside; drop the whole scallion greens into the boiling water and remove instantly. Setting the water aside for use later, cut the scallion greens in half lengthwise to make long, thin strings.
||Combine the ground pork, ground beef, 2 teaspoons fish sauce, garlic, 1/8 teaspoon black pepper, and the shallots. Mix well with your hands.
||Fill each cabbage leaf with 2 teaspoons of the meat mixture. Shape into a cylinder 2 inches across the wide part of the leaf. Fold the sides over to enclose the meat and roll as for spring rolls. Tie a scallion string around the center of each cabbage roll.
||Bring the reserved water to a boil. Add the 2 tablespoons fish sauce, salt, and MSG and drop the cabbage rolls into the boiling liquid. Boil gently, at medium heat, for 15 minutes, partially covered.
||To serve, transfer the soup to a tureen and sprinkle on top the chopped coriander and scallion and some black pepper. Fill individual bowls two thirds full of rice. Add soup until it comes up to the level of the rice; then place some cabbage rolls on top. The remaining soup and cabbage rolls can remain in the tureen for additional servings.
||This soup can also be served without rice.