Step 1: Prepare the ribs. Remove the thin membrane from the bone-side of each rib rack. To do this, use a butter knife to lift a corner of the membrane, then grasp it with a paper towel and pull firmly to remove it in one piece. Pat the ribs dry with paper towels.
Step 2: Make the dry rub. In a small bowl, combine brown sugar, smoked paprika, garlic powder, onion powder, kosher salt, black pepper, and cayenne pepper (if using). Mix well.
Step 3: Season the ribs. Generously sprinkle the dry rub all over both sides of the rib racks, massaging it gently into the meat. For best results, let the seasoned ribs sit at room temperature for 30 minutes, or refrigerate for 2-4 hours (or overnight) to allow flavors to meld, then bring back to room temperature before baking.
Step 4: Preheat the oven. Preheat your oven to 275°F (135°C).
Step 5: Wrap the ribs. Place each rib rack on a large sheet of heavy-duty aluminum foil. Wrap tightly with two layers of foil, creating a sealed packet. Ensure no steam can escape.
Step 6: Slow bake. Place the foil-wrapped ribs on a baking sheet and bake for 2.5 to 3 hours, or until the meat is very tender and has pulled back from the ends of the bones.
Step 7: Sauce the ribs. Carefully remove the ribs from the oven. Increase the oven temperature to 375°F (190°C). Unwrap the ribs and discard the foil and any accumulated liquid. Place the ribs directly on a clean baking sheet (lined with foil for easy cleanup, if desired). Generously brush both sides of the ribs with your favorite BBQ sauce.
Step 8: Finish baking. Return the sauced ribs to the oven and bake for another 15-20 minutes, or until the sauce is caramelized and slightly sticky. For extra char, you can broil for 2-3 minutes, watching carefully to prevent burning.
Step 9: Rest and serve. Let the ribs rest for 5-10 minutes before slicing between the bones and serving. Enjoy your delicious Baby Back Ribs Recipe!