Preheat oven to 275 degrees F (135 degrees C).

Remove the thin membrane from the back of the rack by sliding a knife underneath it and pulling it off with a dry kitchen towel for grip.

Generously season both sides of the ribs with salt and ground black pepper.

Place ribs meatiest side down in your roasting pan or rimmed baking sheet and cover tightly with aluminum foil.

Bake for 2.5 to 3.5 hours until meat easily falls from the bones. Check after 2 hours by piercing the thickest part with a thin knife. It should slide through with little to no resistance. If still tough at 3.5 hours, increase oven to 300 degrees F and continue baking in 20-minute intervals.

While ribs bake, make the BBQ sauce. Heat olive oil in a small saucepan over medium heat. Cook diced onion for 5 to 8 minutes until soft. Add cumin and stir for 30 seconds. Stir in ketchup, hot chili sauce, brown sugar, and apple cider vinegar. Season with salt and cook for 2 minutes. Remove from heat and set aside.

Remove ribs from oven and carefully discard foil. Generously brush both sides of the rack with BBQ sauce using a pastry brush.

Move oven rack to the top position and broil on high for 3 to 4 minutes until sauce caramelizes and begins to char at the edges. Watch closely the entire time to avoid burning. Serve immediately.