Preheat oven to 300 degrees F. with an oven rack in the center of the oven. Line a large rimmed baking sheet with foil. Combine the ingredients for the dry rub in a small bowl.

Remove the ribs from their packaging and rinse under cool water. Dry well with paper towels. If the ribs have a membrane intact, insert a knife under it to lift it, grab hold of it with a paper towel, and peel it off.

Set the ribs, meaty side down, on a sheet of heavy duty foil that is large enough to enclose it. Sprinkle about one-third of the seasoning mix over the bony side of the ribs and use your hands to rub it all over. Flip the ribs over and sprinkle the meaty side with the remaining seasoning, spreading it out over the ribs with your hands. Enclose the ribs in the foil and place the foil packet on the foil-lined baking sheet. If using two racks, divide the seasoning between the two racks and wrap them in separate pieces of foil. Transfer the ribs to the oven.

Bake for 2 hours, or until very tender when pierced with a fork.

Remove the ribs from the oven and set the oven to BROIL with the oven rack still in the center of the oven. Lift the foil packet containing the ribs from the baking sheet. Open the foil and use tongs to transfer the ribs to the foil-lined baking sheet, meaty side down. Baste the bony side with BBQ sauce, then flip and generously baste the meaty side. Return the baking sheet to the oven and broil for 4 to 6 minutes, or until the sauce begins to caramelize.

Remove from the oven and let the ribs rest for about 5 minutes. Then, transfer to a cutting board and use a serrated knife to slice into individual ribs.