Cut the top and bottom off the onion and peel off the brown layers of skin. Then cut the onion into 8 wedges, making sure not to cut all the way through the onion.

Gently separate out the wedges as much as you can without breaking any of them. Then put the onion on top of a large piece of foil.

Generously drizzle the onion with oil. Then generously sprinkle with salt and black pepper. Then generously drizzle with sriracha if using.

Grate the cheese and stuff it into the crevices of the onion. Get as much as you can in there without breaking the onion. I can usually get half a block in there.

Tightly wrap the onion in the foil, leaving no gaps. Then place it directly on the barbeque and put the lid on for 30 minutes.

Transfer the onion to a plate, it will leak a lot of juice. Carefully open the foil, divide the onion up and enjoy.