In a large bowl, mix the ground beef with bread crumbs, sweet corn, egg and chopped scallion. Then, add onion powder, pepper and salt and mix again.
Cut the top of the bun, remove the inside of the bun and spoon beef mixture in the cups to fill just 1/3 of the empty bun.
Add one cube of cheese and then top it with another spoon of the beef mixture.
Repeat these steps with each bun.
Wrap each bun with aluminium foil and bake at 180°C or at medium heat for 14-15 minutes or until beef is cooked.
Remove the foil and top the buns with Parmesan and mozzarella cheese.
Put back in the oven for 2-3 minutes or until cheese is melted and golden.
1- After removing the inside of the bun, you can use it as bread crumbs.
2- Avoid over stuffing the buns with the beef mixture in order to have enough space at the top to add Parmesan and Mozzarella cheese.