In Vietnam, giant taro (Colocasia gigantea) is known as dọc mùng (or bạc hà in some provinces in the south). It’s the stem of this taro species, not the taro itself, that is often used in Vietnamese sour soup and noodle soups.
The Giant Taro Stem Noodle Soup (bún dọc mùng) is a common dish in northern Vietnamese homes during hot summer. You may also found this dish in some local restaurants in Hanoi.
As the name suggests, the main ingredients of this noodle soup is bún (Vietnamese soft rice vermicelli) and giant taro stem slices. In fact, the hidden important ingredients are pork bones (for the broth) and meatballs (for toppings).
Wash the pork ribs then blanch and rinse them with filtered water and then put in the pot to simmer for about 40 minutes. Add a pinch of salt and skim off the foam during the simmering process to make the broth clearer. If you want to cook this noodle soup dish for breakfast, you can prepare the broth the night before.
Peel the green skins of the taro stems, cut into diagonal 3-5 cm pieces and then rinse with water 1 more time. Add a little sea salt to the taro stem slices and use your hands to stir up a few times and then rinse with water. Repeat this 3-5 times so that those slices won't give itching feelings.
Rinse the mushrooms with cold water and then soak in boiling or warm water for about 15 minutes so that the mushrooms will expand in size. Cut off the roots and finely chop the mushrooms.
Mix the finely ground pork with shiitake mushrooms, wood ears and chopped shallots. Add to the mixture ½ tablespoon granule seasoning, 2 teaspoons fish sauce, 1 teaspoon finely ground pepper. Wear plastic gloves and rub a layer of oil on your hands and then roll the ground pork into round bite-sized balls. Place the meatballs in the fridge for some time.
Once the ribs are simmered, turn on the high heat to bring to a boil, then add the meatballs into the broth, wait until they are cooked and float on the surface of the water, then add granule seasoning and soup powder to taste. Next, add the taro stem pieces until they expand in size.
Blanch the rice noodle in a pot of boiling water, then place it in a bowl. Add pork ribs, meatballs, and taro stem. Sprinkle some chopped green onions and coriander then pour the broth into the bowl. Enjoy the dish while it is still hot.
You can add tomato wedges when preparing the broth, and add dried bamboo shoots as additional vegetable. The dish may be served with some condiments like lime wedges, and chili sauce.