Sauté the sliced onion in a skillet until softened and beginning to brown (about 8 minutes). Add garlic, cook 30 seconds, then add ground beef. Brown the beef, drain any excess fat, then stir in barbecue sauce, Worcestershire sauce, smoked paprika, salt and pepper. Simmer briefly until saucy.

Preheat oven to 350°F (175°C). Slice the Hawaiian roll bundle horizontally, place the bottom half in a 9x13 baking dish, spread the beef mixture evenly, layer cheese halves, add optional pickles or jalapeños, then place the top half of the rolls over everything.

Whisk melted butter, brown sugar, and garlic powder. Brush the mixture over the top of the rolls and sprinkle sesame seeds if using. Bake 12–15 minutes until cheese is melted and tops are golden. Broil 1–2 minutes if you want extra browning. Let rest 2–3 minutes, then separate and serve.