(Calculate per person 1/2 rack of ribs; this recipe is for 4 people)
For the Rub
6 tablespoons mustard (I used dijon, but use whatever you have)
2 tablespoons ketchup
3 medium cloves garlic, minced or pressed through garlic press (about 1 tablespoon)
2 teaspoons ground black pepper
1 tablespoon sweet paprika
1 tablespoon chili powder
1/2 teaspoon cayenne pepper
1 1/2 tablespoons kosher salt
3 tablespoons brown sugar
For the Ribs
2 racks Babyback spareribs, 2 1/2 to 3 pounds each, trimmed of surface fat, membrane removed, each rack cut in half
1/4 cup Lapsang Souchong tea leaves (finely ground), about 10 tea bags
1/2 cup apple juice
For the Sauce
1 medium onion, peeled and quartered
1/4 cup water
1 cup ketchup
5 tablespoons molasses
2 tablespoons cider vinegar
2 tablespoons Worcestershire sauce
2 tablespoons Dijon mustard
1 1/2 teaspoons liquid smoke (optional)
1 teaspoon hot pepper sauce
1/4 teaspoon ground black pepper
2 tablespoons vegetable oil
1 medium clove garlic, minced or pressed through a garlic press (about 1 teaspoon)
1 teaspoon chili powder
1/4 teaspoon cayenne pepper
For the Rub: Combine mustard, ketchup, and garlic in small bowl; combine pepper, paprika, chili powder, cayenne, salt, and sugar in separate small bowl. Spread mustard mixture in thin, even layer over both sides of ribs; coat both sides with spice mixture, then wrap ribs in plastic and refrigerate for at least 8 hours and up to 24 hours.
Transfer ribs from refrigerator to freezer for 45 minutes. Adjust one oven rack to lowest position and second rack to upper-middle position (at least 5 inches below broiler). Place baking stone on lower rack; heat oven to 500 degrees. Sprinkle ground tea evenly over bottom of rimmed baking sheet; set wire rack on sheet. Place ribs meat side up on rack and cover with heavy-duty foil, crimping edges tightly to seal. Roast ribs directly on stone for 30 minutes, then reduce oven temperature to 250 degrees, leaving oven door open for 1 minute to cool. While oven is open, carefully open one corner of foil and pour apple juice into bottom of baking sheet; reseal foil. Continue to roast until meat is very tender and begins to pull away from bones, about 2 hours. (Begin to check ribs after 1 1/2 hours; leave loosely covered with foil for remaining cooking time.)
While your ribs are in the oven, prepare your barbeque sauce. Process the onion with the water in a food processor until pureed and the mixture resembles slush, about 30 seconds. Strain the mixture through a fine-mesh strainer into a liquid measuring cup, pressing on the solids with a rubber spatula to obtain 1/2 cup juice. Discard the solids. Whisk the onion juice, ketchup, molasses, vinegar, Worcestershire, mustard, liquid smoke (if using), hot pepper sauce, and black pepper together in a medium bowl. Heat the oil in a large nonreactive saucepan over medium heat until shimmering but not smoking. Add the garlic, chili powder, and cayenne and cook until fragrant, about 30 seconds. Whisk in the ketchup mixture and bring to a boil; reduce the heat to medium-low and simmer gently, uncovered, until the flavors meld and the sauce is thickened, about 25 minutes. Cool the sauce to room temperature before using.
After the 1 1/2 to 2 hours, fire up your grill to a medium-hot temperature.
Remove ribs from oven and slather on barbeque sauce. Bring outside and carefully place racks on the grill (at this point, they are very “fall off the bone”, so be gentle). Brown ribs until crispy in spots, 5 to 10 minutes. Flip ribs meat side up and cook until well browned and crispy, 5 to 7 minutes more. Cool for at least 10 minutes before cutting into individual ribs. Serve with additional barbecue sauce, if desired.
Note: If you don’t have a grill — or it is the dead of winter — you can also do this last step using your oven’s broiler.