In a large Dutch oven over medium, combine the oil, garlic, ginger and the white scallion parts. Cook, stirring, until sizzling, about 3 minutes. Stir in the star anise and peppercorns, then cook until fragrant, about 30 seconds.

Stir in the chili-bean sauce, tomato paste and brown sugar, then pour in the soy sauce, rice wine and water. Bring to a boil over high.

Add the beef shanks and return to a simmer. Cover, reduce to low and cook, adjusting as needed to maintain a gentle simmer, until the beef is tender and beginning to fall apart, about 2 hours.

Use a slotted spoon to transfer the beef shanks to a bowl and set aside. Strain the liquids, discarding the solids, into a bowl. Reserve the pot. Skim off and discard the fat from the surface of the liquid, then return to the pot.

When cool enough to handle, shred the meat into bite-size pieces, discarding the bones, fat and gristle. Add the meat to the pot and bring to a simmer over medium-high, then reduce to low and cover to keep warm.