Divide the bread dough into 24 equal pieces, roll into balls, cover with a towel.
Spray a cast-iron pan with non-stick cooking spray or brush with olive oil. Set aside.
Working with one piece of dough at a time, pat it out to a circle of roughly 3 to 4 inches. Place one slice of cheese and one meatball on the circle. Gather up the edges around the meatball and cheese, and gently pinch closed. Place seam side down against the inside edge of the cast iron pan. Repeat with remaining bread dough, cheese, and meatballs, arranging the rolls in two concentric circles, leaving an opening in the center.
Cover with a towel and let rise in a warm, draft-free place for about 25 minutes. Preheat the oven to 375°F.
Pour the barbecue baked beans into open area in the center of the pan. Whisk together the beaten egg with the barbecue sauce and brush over the rolls. Sprinkle the sesame seeds evenly over the rolls. Bake for 25-32 minutes, or until the rolls are set and deep golden brown. To get a little more colour on top, you can place the rolls briefly under a broiler, about 2 minutes. Garnish with chopped green onions.
Place a trivet on the table and serve hot directly from the pan with barbecue sauce on the side for dipping.