Place the oxtail and beef bones into a pot and fill water to cover them. Bring it to a boil and blanch for roughly 10 minutes.
2 lbs Oxtail, 2 lbs Beef Bones
Use a colander and strain the hot water out from the pot and rinse the bones and oxtail with water and clean off any scum on the bones and oxtail.
Place oxtail and beef bones back into a pot and fill it with 8 litres of water and bring it to a boil. Add salt once it begins to boil. Leave it on a rolling boil for 30 minutes and continue skimming off any scum that rises to the surface if there are any.
1 tbsp Salt
While the broth is boiling, wash and peel the radish and slice them into roughly 1 inch thick pieces. In addition, give the cinnamon sticks and star anise a quick rinse and soak the black cardamom pods in a small bowl of water. Add the cinnamon sticks, star anise, and radish into the broth after it has boiled for 30 minutes.
1-2 Radish, 2 Cinnamon Sticks, 5 Star Anise, 4 Black Cardamom Pods
Bring the pot to a simmer and peel 2 whole onions and add into the pot.
Add 1/4 cup of fish sauce (depending on the fish sauce brand you have, you may want to add a bit more or less of the portion), 1/4 cup of soy sauce, 50g of rock sugar to the broth. Do not over season the broth right now as you want to focus on getting the flavor of the beef out first. Seasoning flavor can be adjusted near the end, if needed.
1/4 cup Soy Sauce, 1/4 cup Fish Sauce, 50 grams Rock Sugar
Rinse the beef tendon and put it into the pot. The beef tendon will add creaminess to the broth from its collagen. Once the tendon is more tender at a later point in time, it is then ready to be cut.
1 lbs Tendon (or 2-3 tendons)
Let the broth simmer for 4-6 hours. The longer the duration the stronger the beef flavor will come through. Check up on the broth every 1-2 hours and skim out any oil or fat on the surface. Give the broth a quick stir once in awhile. As you simmer the broth longer, the water level will decrease. Make sure your broth level is maintaining around 7 litres (with the ingredients in the broth). Add extra water to the broth, if necessary, to maintain the 7 litre mark.
After simmering the broth for 3 hours, check on the tenderness of the tendon. Place the tendon in a ladle and shake the ladle. If the tendon shakes like a jello then the tendon is ready to be cut into small pieces for toppings. If you'd like the tendon to be more soft or would like the broth to be more creamy, then keep the tendon in the broth for longer before cutting it.
Within the last 2 hour mark, add the black cardamom pods to the broth and give the broth a quick stir.
Within the last 1 hour mark, do a taste test and tweak flavor to your liking by adding more salt, fish sauce, or rock sugar.