Preheat the oven to 300°F (150°C). Lightly grease a large baking dish.
Prepare the spice rub: In a mixing bowl, combine brown sugar, smoked paprika, garlic powder, onion powder, salt, black pepper, and chili powder.
Season the ribs: Pat the boneless pork ribs dry with paper towels. Rub the seasoning mix generously all over the ribs, coating each piece well.
Arrange ribs: Place the seasoned ribs in a single layer in the baking dish. Cover tightly with aluminum foil.
Bake low and slow: Roast the ribs in the preheated oven for about 2 hours, until they are tender and juicy.
Add the sauce: Carefully remove the foil. Brush the ribs generously with barbecue sauce.
Broil for finish: Turn the oven to broil. Broil the ribs uncovered for 2–5 minutes until the sauce caramelizes slightly. Watch closely to avoid burning.
Rest and serve: Let the ribs rest for 10 minutes before slicing or serving.