Soak the oxtail in cold water for 1 hour, changing the water a few times. Transfer the oxtail to a large pot of water, bring to a boil, and lower the heat to simmer for 15 minutes. Drain and rinse under cold water to remove foam and scum. Set aside. Tip: Soaking and blanching the oxtail before cooking will remove any blood and impurities.
To Sear Stew Beef
In a large heavy-bottom pot (you will need a 6.75 to 8 QT pot), heat 1 Tbsp oil over medium-high heat and sear the surface of the stew beef. Once seared, transfer to a plate and set aside. Tip: This step will enhance the savory flavor.
To Cook Oxtail Soup
In the same pot, heat 1 ½ Tbsp oil on medium heat and sauté onion and celery until they are tender.
Add the seared stew beef, carrot, cabbage, tomatoes, beef broth, and tomato paste and bring it to a boil.
Add the oxtails. Once it boils, lower the heat and simmer for 20 minutes. With a fine-mesh sieve, skim off the scum and foam on the soup’s surface. This step can be tedious but it’s the key to a clean taste when you drink the soup.
Add Seasonings A and reduce heat to medium-low or low. Cover and simmer (not boiling) for at least 3-4 hours, or until meat comes off from oxtail bones and becomes tender.
Add potatoes and cook until tender, about 15 minutes.
Stir in Seasonings B and mix well. Ladle the soup to individual bowls. Enjoy!
You can keep the leftovers in an airtight container or in the pot and store in the refrigerator for up to 3 days or in the freezer for a month. Remove the potatoes as they change the texture when frozen.
The recipe is adapted from a food blog, Lulu at Home (but no longer exist).