Lightly coat the interior of a 6-quart slow cooker with cooking spray to prevent sticking and facilitate easier cleanup.

Remove the thin membrane from the underside of the baby back ribs. Discard the membrane. Arrange the ribs inside the slow cooker, curving them along the sides if necessary to fit.

In a small mixing bowl, combine the barbecue sauce, brown sugar, minced garlic, Worcestershire sauce, and cayenne pepper (if using). Stir thoroughly until well blended.

Pour half of the prepared sauce evenly over the ribs, ensuring they are well coated. Reserve the remaining sauce in the refrigerator for later use. Season the ribs with salt and freshly ground black pepper to taste.

Cover the slow cooker with the lid and cook on the low setting for 7 to 9 hours, or on the high setting for 3 to 5 hours, until the ribs are tender and the meat easily pulls away from the bone.

Carefully transfer the cooked ribs to a baking sheet lined with parchment paper. In a small bowl, combine half of the cooking juices from the slow cooker with the reserved sauce. Brush the ribs generously with this sauce mixture.

Place the ribs in a preheated oven set to 400°F (220°C) and broil for approximately 10 minutes, or until the sauce begins to caramelize and lightly crisp along the edges.

Remove from the oven and serve warm with the remaining sauce on the side.