Remove any tough outer cabbage leaves, core the cabbage, and cut it into thick wedges or wide ribbons, keeping the pieces fairly large.

Pat the pork belly slabs dry with paper towels.

Sprinkle the pork belly all over with the kosher salt and freshly ground black pepper, rubbing the seasoning in lightly with your hands.

Arrange the sliced cabbage in an even layer in the bottom of a 5- to 6-quart slow cooker.

Lay the seasoned pork belly slabs in a single layer on top of the cabbage, fitting them snugly without piling them too much on top of each other.

Cover and cook on LOW for 7 to 8 hours, or on HIGH for 4 to 5 hours, until the pork belly is very tender when pierced with a fork and the cabbage is soft, wilted, and glossy with rendered fat and juices.

For crisp, caramelized edges, carefully lift the cooked pork belly slabs out with tongs, place them on a foil-lined baking sheet, spoon a little slow cooker juice and rendered fat over the top, and broil on the top rack for 3 to 6 minutes while watching closely.

While the pork belly is under the broiler, toss the cabbage in the slow cooker so the leaves are coated in the juices, then taste and add more salt or pepper if needed.

Spoon a generous bed of cabbage onto plates or a warm serving platter, top with the pork belly slabs, and spoon a little extra juice over everything before serving hot.