Make the spice rub:
In a small bowl, stir together all the ingredients.
Cook the ribs:
Position a rack in the center of the oven and heat the oven to 300°F. Sprinkle and press 1/4 cup of the rub on both sides of each rib rack. Put the racks, meaty side up, on a broiling pan or a wire roasting rack set over a baking sheet. Lightly season the ribs with salt and put them in the oven. After the first hour, rotate the pan every 30 min. (Note: If you use two baking sheets, switch their position in the oven, too). The ribs will sizzle gently as they cook, and they’ll become tender after about 2 hours in the oven.
To test for doneness, pick up the center of the ribs with tongs; the ends of the ribs should flop downward (this means the fat and cartilage have broken down), and a skewer inserted between the ribs should meet little resistance. If the meat between the ribs is still tough, keep cooking, checking every 15 minutes and rotating the pan.
Remove the rib racks from the oven, put them on a cutting board meaty side down (so they’re easier to slice), and slice them into individual ribs. Arrange the ribs on a platter (or stack them for a festive presentation), garnish with scallions, if you like, and serve with the dipping sauce on the side.
Make Ahead Tips
The tender, fatty meat of the ribs makes them hold up well to reheating. You can cook the ribs a day ahead and reheat them uncut, loosely covered with foil, in a 250°F oven until warmed through, 20 to 30 min.
nutrition information (per serving):
per rib, based on 26 ribs;
Photo: Scott Phillips