Lightly butter the bread on both sides.
To one piece of bread, add a nice grating of good-quality cheese that melts well, like Cheddar, Red Leicester or a mixture of the two. Place your second piece of bread on top, then cook in a sturdy non-stick frying pan on a medium heat for about 3 minutes on each side. This is important, because if it gets too coloured too quickly you won’t get the gorgeous ooze and melt in the middle, and this is all about encouraging that internal cheese lava flow. As it cooks, rest something flat with a little weight on top to ensure maximum surface area and crunch.
When lightly golden on both sides, lift the toast out of the pan and grate a little layer of cheese into the pan where it was sitting. Place the toast back on top and grate some more cheese on the top side. Leave it for just over 1 minute – wait for the cheese to bubble and the fat to spill out of it, then add a little pinch of cayenne pepper.
Give the toast a poke, and once it has a cheesy, doily-like crust on the bottom that moves as one, lift it out of the pan and hold it on the fish slice for 30 seconds so the melted cheese hangs down, sets hard and forms an impressive cheese crown. Flip it onto the other side and once golden, serve, remembering to let it cool for a couple of minutes before attempting to tuck in.