Step 1

In a small bowl, combine the chile powder, five-spice powder, brown sugar, 2 tsp. salt, and 1 tsp. pepper. Sprinkle generously all over the ribs. Cover and refrigerate for at least 2 hours but preferably overnight.

Step 2

Prepare a gas grill for direct grilling over medium-high heat. Grill the ribs until all sides are nicely browned, 1 to 2 minutes per side. Let cool briefly and then tie with a couple of loops of butcher’s twine.

Step 3

Prepare the grill for indirect grilling. Set an 8-quart heavy-duty pot over medium heat and when hot, add the oil. Add the onions and cook, stirring occasionally, until soft, about 5 minutes. Add the garlic and ginger and stir for 1 minute more. Pour in the chicken broth, 1/4 cup of the vinegar, 1 Tbs. of the brown sugar, the fish sauce, and the soy sauce. Add the star anise, bring to a boil, and then remove from the heat.

Step 4

Put the ribs in the pot and set the pot on the grill over the cool zone. Cover the pot, close the grill lid, and cook for 30 minutes. Check the ribs and rearrange so they remain submerged in the simmering liquid. Check the ribs again after 30 minutes and move them around if necessary. After another 30 minutes, check the ribs for tenderness. They should be fork-tender but not falling apart. If they’re not tender enough, continue to cook, checking every 15 minutes. Remove the ribs from the pot and set aside.

Step 5

Pour the liquid into a heatproof vessel, such as a Pyrex measuring cup, and let sit until the fat rises to the top. Skim off and discard the fat. Taste the liquid; if it’s too watery, return to the pot and boil over high heat until flavorful.

Step 6

Prepare the grill for direct grilling over medium-high heat. Pour 1 cup of the braising liquid into a small saucepan and stir in the remaining 2 Tbs. brown sugar and 2 tsp. rice vinegar. Over medium-high heat, reduce the liquid until it becomes syrupy, about 12 minutes—you’ll have about 1/3 cup.

Step 7

Brush the glaze over one side of each short rib and grill glazed side down until the glaze begins to bubble and lightly darken, 2 to 3 minutes. Brush another surface with the glaze and turn the ribs. Continue to brush and glaze, turning frequently, until all sides are nicely glazed. Transfer the ribs to a warm platter, drizzle with the remaining braising liquid, and garnish with the scallions and cilantro.