Step 1: Prepare Your Ribs. Pat the baby back ribs dry with paper towels. Carefully remove the thin membrane from the bone-side of each rack. Slide a knife or spoon handle under one edge, then grip with a paper towel and pull it off. Repeat if necessary.
Step 2: Apply the Dry Rub. In a small bowl, combine 1/2 cup brown sugar, paprika, garlic powder, onion powder, chili powder (if using), black pepper, and salt. Mix well. Generously rub this mixture all over both sides of the ribs, massaging it into the meat. Let the seasoned ribs sit at room temperature for 30 minutes, or cover and refrigerate for 2-8 hours.
Step 3: Preheat Oven & Prepare for Baking. Preheat your oven to 275°F (135°C). Lay out two large sheets of heavy-duty aluminum foil for each rack of ribs, perpendicular to each other, to create a cross. Place one rack of seasoned ribs in the center, meat-side up. Tightly seal the foil around the ribs, creating a secure package. Place the foil-wrapped ribs on a baking sheet.
Step 4: Slow Cook for Tenderness. Bake the ribs in the preheated oven for 2.5 to 3 hours, or until they are extremely tender and the bones feel loose when gently twisted.
Step 5: Prepare Your BBQ Sauce. While the ribs are cooking, prepare your BBQ sauce. In a small saucepan, combine your favorite BBQ sauce, apple cider vinegar, 1 tablespoon brown sugar (if using), and Worcestershire sauce (if using). Simmer over low heat for 10-15 minutes, stirring occasionally, until slightly thickened. Set aside.
Step 6: Glaze & Finish. Carefully remove the ribs from the oven and unwrap the foil (beware of hot steam!). Drain off any liquid from the foil. Increase the oven temperature to 400°F (200°C) or set your broiler to high. Place the unwrapped ribs directly on the baking sheet, meat-side up. Brush a generous layer of the prepared BBQ sauce over the top of the ribs. Return them to the oven or broiler for 10-15 minutes, or until the sauce is caramelized and sticky. Watch closely to prevent burning.
Step 7: Rest & Serve. Once glazed and caramelized, remove the ribs from the oven. Tent them loosely with foil and let them rest for 10-15 minutes before slicing. This allows the juices to redistribute. Slice the ribs between the bones and serve immediately with your favorite sides.