Taiwanese Pork Belly Buns

For the Pork Belly:

2 tablespoons vegetable or peanut oil
One (1-pound) slab skin-on pork belly, cut into 2-inch strips, then sliced 1/4 inch thick
2 medium cloves garlic, crushed
2 (⅛th-inch) slices fresh ginger (unpeeled)
1 star anise pod (optional)
1 small fresh red chile, such as Thai chile (optional)
2 tablespoons rock, brown or raw sugar
¼ cup Asian rice wine
½ teaspoon five-spice powder (see note)
¼ cup dark soy sauce
¼ cup light soy sauce
4 cups water

For the Buns and Toppings:

For the Pork Belly: Heat the oil over medium-high heat in a large skillet or wok. Cook pork belly until lightly browned on the bottom, about 3 minutes. Flip pork belly and cook until lightly browned, about 2 minutes longer. Transfer pork belly to a plate and set aside.
In the same skillet, add garlic and ginger and cook over medium-high heat, stirring, until fragrant. Add star anise and chile (if using), and sugar and cook, stirring, until the sugar is melted and bubbling, about 2 minutes. Add rice wine and bring to a boil, stirring until sugar dissolves, about 2 minutes. Add five-spice powder, dark and light soy sauces, and water and bring to a boil.
Return pork belly to the skillet and reduce heat to low. Cover skillet and cook until pork belly is very tender, at least 1 hour or preferably 2 hours.
For the Buns and Toppings: Meanwhile, combine peanuts and sugar in a blender or food processor and pulse, stopping to scrape down the sides, until the mixture resembles a coarse powder, about 1 minute.
Set a steamer over a pot of boiling water. Add buns, cover steamer and cook until buns are heated through and fluffy, about 3 minutes.
To Serve: Spread pickled mustard greens inside each steamed bun and set a piece of pork belly on top of mustard greens. Top pork belly with a pinch of chopped cilantro and a sprinkle of peanut powder. Serve immediately.

Find five-spice powder, fresh or frozen Chinese-style steamed buns, jarred pickled mustard greens, and rock sugar at Asian grocery stores