Fall-off-the-bone oven baked ribs with a homemade sweet and smoky rub, baked low and slow, then finished hot with a sticky BBQ glaze. No grill or smoker needed.
Heat the oven to 275°F. Cover a large rimmed baking sheet with heavy-duty foil to make cleanup easier.
Place the ribs on the pan, bones up, and blot away surface moisture with paper towels. If the membrane is still intact, work the tip of a butter knife underneath one edge until you can lift enough to grab. Hold the loosened piece with a paper towel, then peel the membrane away from the rack.
Make the rib rub by adding the dark brown sugar, smoked paprika, sea salt, black pepper, garlic powder, onion powder, chili powder, dry mustard, cocoa powder, cumin, oregano, celery seed, allspice, and cayenne to a medium bowl. Stir thoroughly, breaking apart any packed pieces of brown sugar so the spices are evenly distributed.
Blot the ribs again with clean paper towels, especially anywhere moisture collected while you prepared the seasoning. Brush a light coating of yellow mustard across the front and back of each rack.
Coat the ribs generously on both sides with the rub. Instead of rubbing it back and forth, press the mixture firmly onto the meat with your hands to leave a substantial layer of seasoning in place.
Cover and bake. With the ribs positioned meaty side up, lay foil over the entire baking sheet and crimp it firmly around the rim. Transfer the covered pan to the 275°F oven and leave the ribs undisturbed for 2 ½ hours.
Check for tenderness. Carefully peel back the foil, watching for hot steam. There will be some excess liquid, and you can pour it off now or leave it in the pan. The meat should be beginning to pull away from the tips of the bones, and a toothpick or knife inserted between two bones should pass through without much resistance. If you are checking with a thermometer, look for an internal temperature around 195-205°F. Racks that still feel firm need more time. Reseal the pan and give them another 20-30 minutes at 275°F before checking again.
Sauce the ribs. When they have reached the desired tenderness, raise the oven temperature to 400°F. While the oven heats, brush ½ cup BBQ sauce over the top and sides of each rack.
Finish uncovered. Once the oven reaches 400°F, return the ribs to the oven with no foil. Bake for 15 minutes, then add the remaining BBQ sauce. Cook an additional 15-20 minutes, until the sauce has thickened into a sticky glaze and begins to caramelize around the edges. For even more caramelization, switch the oven to broil for 3-4 minutes. Stay close to the oven during this step, because the ribs can go from caramelized to scorched quickly.
Rest the ribs for 10 minutes before slicing.
Notes
Remove the membrane: taking the thin membrane off the back of the ribs helps them get more tender and lets the seasoning reach the meat.Keep the pan tightly covered: a tight foil seal traps moisture while the ribs bake, which is what makes them fall-off-the-bone tender.Cooking time varies: depending on the thickness of the racks, they may need an extra 20-30 minutes at 275°F.Check for doneness: the ribs are ready when the meat has pulled back from the ends of the bones and a toothpick or thin knife slides easily between the bones.BBQ sauce: use a thick sauce so it clings to the ribs. Sweeter sauces caramelize faster during the final bake, so watch them closely.Make ahead: bake through the covered stage a day early, refrigerate, then sauce and finish uncovered at 400°F for 30-35 minutes.