Place oxtail pieces in a large pot and cover with water. Bring to a boil for ten minutes. This removes impurities and excess fat. Drain the water and rinse the meat thoroughly under cold water.

Clean the pot and return the rinsed oxtails to it. Add ten cups of fresh cold water. Throw in the smashed ginger and star anise. This creates the fragrant base for your delicious soup.

Add the raw peanuts and dried orange peel to the pot. The orange peel adds a subtle, citrusy depth. The peanuts soften beautifully and absorb the beefy flavors. These are essential for the authentic taste.

Bring the liquid to a gentle boil, then reduce heat. Cover the pot and simmer for about three hours. The meat should be very tender. Skim any fat from the surface occasionally.

Once the meat is tender, add salt and soy sauce. Taste the broth and adjust the seasoning if needed. The flavor should be balanced and savory. Do not rush this slow-cooking process.

Wash the mustard cabbage and cut it into bite-sized pieces. Add the cabbage to the pot in the last ten minutes. Cook until it is wilted but still slightly bright green.

While the cabbage cooks, grate plenty of fresh ginger. Put the ginger in small individual sauce bowls. Pour soy sauce over the ginger. This is for dipping the tender meat later.

Ladle the hot soup into deep bowls. Make sure everyone gets several oxtail pieces and peanuts. Top generously with fresh cilantro and sliced green onions. Serve immediately with a side of white rice.