Sweet and tangy barbecue sauce: combine all barbecue sauce ingredients in a small pot over medium heat and bring to a simmer.

Simmer for 10 to 15 minutes. At this point, the sauce should be thickened and sticky. 

Remove from the heat and store the barbecue sauce in a sealed container in the refrigerator. 

Oven-baked pork belly slices: preheat your oven to 400 F. Season both sides of the pork belly slices with an even sprinkling of salt and ground black pepper.

Line a sheet pan with parchment paper and place the seasoned pork belly slices on the paper. Bake for 20 minutes and remove the pan from the oven. Flip each pork belly slice over and paint the top of each slice with barbecue sauce. Return the pan to the oven to bake for another 10 to 20 minutes. 

Remove the pan again. Flip the pork belly once again and paint the top with more sauce. At this point, you can serve or if you would like more browning on top of the pork belly you can turn on the oven broiler to high and broil for 4 to 5 minutes or until the top is crispy and the barbecue sauce is browning. 

Sandwich assembly: slice your roll and toast the interior if desired.

Add a little barbecue sauce to the bottom of the roll. Top the barbecue sauce with slices of the pork belly. Add more sauce to the top of the pork belly slices.

At this point, if you want a hot sandwich you can place the barbecue sauced bottom half of the sandwich under an oven broiler on high for 2 to 3 minutes. This will heat the meat and sauce. Remove from the broiler and continue. 

Sprinkle some sliced onion and dill pickles slices on top of the pork belly and close the top of the sandwich to serve.