Line a rimmed baking sheet with nonstick foil for easy cleanup. Preheat the oven to 275 degrees F.
Place the ribs in the pan, bone side down. Spray them with oil. Sprinkle with salt and pepper.
Bake the ribs for 1 hour, uncovered.
Meanwhile, mix the barbecue sauce ingredients in a medium bowl, then divide it into three small bowls.
After one hour, take the ribs out of the oven and carefully drain the pan juices. Brush the top of the ribs with a ⅓ of the BBQ sauce and return them to the oven. Wash the basting brush with warm soapy water.
Repeat this after one more hour - brush the top of the ribs with another ⅓ of the BBQ sauce and return them to the oven. Wash the basting brush with warm soapy water.
After one more hour, brush the ribs with the remainder of the sauce. Reduce the oven to 250 degrees F and return the ribs to the oven for one final hour.
After 4 hours, the meat will be very tender and will fall off the bones. The top will be dark and deliciously caramelized. Remove the ribs from the oven, cut them into individual ribs, and serve.
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Notes
The BBQ sauce darkens and caramelizes in the oven. It should be very dark but not burned. So if you think that it's darkening too much, you can loosely cover the ribs with foil during the last one or two hours of baking.It's easiest to cut the ribs when you place them on a cutting board bone-side up and use a sharp chef's knife. When they're bone-side up it's easy to locate the bones and cut in between them. You can cut the slab into one or two-rib portions.