Preheat your oven to 250°F (120°C). Line two baking sheets with foil and place wire racks on top for even cooking.
If your pork belly has the skin intact, score it with a sharp knife in a crisscross pattern before cutting it into cubes. This helps the skin crisp up beautifully during cooking and allows the seasonings to infuse into the fat and meat. For skinless pork belly, skip the scoring and cut the pork directly into 1-inch cubes.
Place the pork belly cubes in a large bowl. Drizzle with olive oil and toss to coat. In a separate bowl, mix the brown sugar, smoked paprika, garlic powder, onion powder, chili powder, salt, and black pepper. Sprinkle the dry rub over the pork belly and toss until evenly coated.
Arrange the seasoned pork belly cubes on the wire racks, leaving space between each piece. Bake for 3 to 3.5 hours, flipping halfway through, until the cubes are tender and have developed a nice crust.
Increase the oven temperature to 400°F (200°C). Remove the pork belly from the racks and place them directly on the baking sheets. Brush each piece generously with barbecue sauce. Return to the oven and bake for another 15-20 minutes, or until the sauce caramelizes and becomes sticky.
Remove the pork belly burnt ends from the oven and let them rest for a few minutes. Serve as a snack, appetizer, or side dish. These crispy, sticky bites are sure to be a hit!