Brown the ground beef in a skillet over medium-high heat. Season with salt and pepper, then drain any excess grease.
Slice the Hawaiian rolls in half horizontally and place the bottom half on a parchment paper lined baking sheet.
Spread a thin layer of mayonnaise over the rolls.
Evenly layer the cooked ground beef over the rolls.
Drizzle generously with BBQ sauce.
Sprinkle the chopped bacon over the BBQ sauce.
Top with slices of cheddar cheese, then add a generous handful of crispy fried onions.
Place the top half of the rolls on. (Optional: Brush the tops with melted butter for extra flavor and browning.)
Cover loosely with foil and bake for 20 minutes. Remove the foil and bake for another 5–8 minutes, or until the cheese is melted and the tops are golden.