Preheat oven to 225 degrees. Get your rinsed and dried ribs laid out on a large sheet of foil. Cut them into half racks to make them easy to handle. Sparingly drizzle with olive oil and rub in. Sprinkle liberally with season salt and granulated garlic. The season salt you use can be something as simple as Lawry's or as complex as a gourmet rib rub. Slice one medium or large onion into rings and layer between and over the racks.
Wrap the foil very tightly sealing up the ribs. Place the foil package on a baking sheet and then into the oven. Let them cook for at least 6 hours, no peeking. Just leave them alone. I like to give them a full 8 hours.
Twenty minutes before you want to eat pull ribs out of the oven, carefully remove them from the foil, they will be falling off the bone. Place the ribs on a broiler pan to rest while you work on the sauce.
Preheat the oven to 425 degrees, pour the liquid from the foil packet into a small sauce pan, put the soft onion rings in the pot too. Over medium heat add the garlic, bottle of BBQ sauce, hot sauce, and the ketchup. Allow sauce to bubble softly, stirring frequently for a few minutes. Taste and adjust flavors to your preference, you can add more hot sauce, spicy mustard, chili powder, honey, Worcestershire, brown sugar, or tomato paste until the sauce is perfect for your family. If you want really smooth sauce you could use a stick blender to mix the onions into the sauce but I love it chunky.
Place the ribs on the broiler pan back into the 425 degree oven for about ten minutes to dry them out just a little. Then spoon the BBQ sauce over the ribs and return to the oven for ten more minutes, keep an eye on them so the sauce will not burn.
Serve with the extra sauce and your favorite BBQ sides like cole slaw, fries, green beans, grits , or corn bread .