Preheat your smoker to 225 degrees F with a fruit wood smoke like apple or cherry wood.
Trim the ends of your baby back ribs and remove the membrane from the back. Combine all of the ingredients for the spice rub and sprinkle liberally on all sides of the ribs.
Place the ribs on the smoker, close the lid, and smoke for 2 hours.
In a large bowl, combine all ingredients for the braising liquid. Whisk to ensure all of the sugar crystals have dissolved.
Remove the ribs from the smoker, place them in an aluminum pan, and increase the heat in your smoker to 325 degrees F.
Pour the braising liquid over the ribs and flip the ribs over a couple of times to coat all sides. Flip the ribs so they are meat side down, cover tightly with foil and return to the grill. Cook at 325 degrees F for 3 hours, or until you see the bones sticking out of the meat about 1/2 inch.
Remove the pan of ribs from the grill and increase the heat again to 400-450 degrees F.
Carefully remove the ribs from the pan to a cutting board. Strain 2 cups of the remaining braising liquid into a medium saucepan. Add in the red pepper jelly and the apple cider vinegar. Bring to a boil and simmer until the sauce has reduced by 1/3.
Slice each rack of ribs into individual ribs. Using tongs, dip each rib into the pan with the BBQ sauce until they are coated on all sides with the BBQ sauce.
Return the ribs to the grill for 3-5 minutes, flipping each rib once to tighten the sauce and add just a little char to the edges of the ribs.
Remove all of the ribs to a serving platter. Sprinkle with the sesame seeds and the scallion greens. Serve with additional BBQ sauce, if desired.