Rinse the beef shank with water, and pat dry with kitchen paper towels.  Use a sharp knife to trim and discard any impurities and excess fat.  Keep the whole beef shank intact, and do not cut it into small pieces yet. 

Clean 12 stalks of green onions thoroughly.  Discard the root end and any wilted, browned, or discolored tops or ends. Next, rinse the green onions to remove dirt or debris under cold water.  Next, cut them lengthwise to about 3 inches long.  Don’t forget to reserve and chop some of the top parts of the green onions into small pieces as garnish. 

Peel, cut, and smash 12 slices of fresh ginger with a meat tenderizer or with the back of your knife to release its aroma.   

Fill a large pot with cold water.  Ensure the water level is enough to cover the beef shank. Add one tablespoon of sea salt, half of the cut scallions stalks, and smashed ginger into the pot. Cover and bring the liquid to a boil over high heat. 

Heat your dutch oven with two tablespoons of vegetable oil on high heat.  Add the second portion of cut green onions, smashed ginger, roughly chopped garlic, and sliced yellow onion into the pot. Cook them for 3 to 4 minutes or until fragrant. 

Add your Roma tomato wedges, three Thai chili, and four tablespoons of spicy bean paste.  Cook them for another 4 to 5 minutes until the tomatoes are softened.

Time to add some sauces to create the broth base. Add one-third of a cup of dark soy sauce, half a cup of light soy sauce, half a cup of Chinese cooking wine, two tablespoons of sesame oil, and some rock sugars.  Cover and bring the liquid to a boil on medium-high heat for another 6 to 8 minutes. 

Stir in cooked sliced beef shanks, mix well, and add 6 cups of water to the pot.  Please ensure all of the ingredients are immersed in the liquid.  If not, add extra water to the pot one cup at a time.

Get a 4×3 inches cheesecloth bag to create your spice sachet; insert your cinnamon stick, bay leaves, and star anises in the bag, tie it up, and ensure they will not float out from the bag during the cooking process. Add it to the pot and mix the ingredients with a wooden spoon. Cover the lid and boil the broth on high heat for 30 minutes. 

After 30 minutes, stir the ingredients to ensure everything cooks evenly.  Cover the lid, lower the temperature, and let the broth simmer on low heat for another two hours. You can check on the broth every hour to ensure the meat is submerged and everything cooks evenly.  Let it simmer for 2 1/2 to 3 hours for the best result.

Remove and discard the spice packet after you finish simmering the beef broth. Heat 2 small pots of water on medium-high heat.  One pot is for blanching the bok choy (Or other vegetables of your choice), and the other is for boiling the noodles. Please note that you do not need to season the water with salt or other seasonings.

Bring the water to a boil.  Add your pre-washed Bok Choy to the pot and blanch it for 3 to 5 mins or until tender. Take them out once they are cooked and set aside.  Do not discard the vegetable water.  In the other pot, cook the noodles according to the package’s instructions. If you are using fresh wheat noodles as I do.  You only need to cook it at a maximum of 2 minutes per serving.

Let’s get ready to assemble the dish. Put noodles, a generous amount of beef shanks, and bok choy in a big bowl.  Pour a ladle of vegetable water into the bowl, and then ladle one to two ladles of beef broth.  Garnish some chopped green onions, Thai red chilies, and cilantro to your liking.