Cube the pork belly into 1-2" cubes. Coat with the yellow mustard and then mix in the OWYD Pork Rub. If you don't have our pork rub yet, you can use whatever sweet & spicy rub you have on hand. I won't judge.
Put the coated pork belly on a wire rack. A jerky rack works well for this.
Put the meat in the smoker and let it smoke for about 2-3 hours.
While the pork belly is smoking, whisk together all the barbecue sauce ingredients in a small saucepan. Bring to a simmer, and let it simmer, stirring frequently, for about 10 minutes. Remove from heat and set aside.
Take the smoked pork belly and place them into a large rectangular baking dish. Sprinkle with brown sugar.
Increase the temperature of the smoker to 325°F.
Place the baking dish with the sugared pork belly into the smoker. Let it cook for about 20-25 minutes.
Toss the burnt ends with about a cup of the barbecue sauce and place back into the smoker. Continue cooking until the fat is rendered and the pork belly bites are soft and tender. It should take about an hour. You can give the pan a shake or two midway to re-coat with barbecue sauce for the best results.