Heat the grill (broiler) setting of your oven to medium.
Melt the butter in a small cast-iron or ovenproof frying pan over medium heat.
Add the corn kernels and fry for 3 minutes.
Add the spring onion, give it a quick stir, then remove from the heat.
Add the mayonnaise and sugar, and season to taste with salt and pepper.
Mix well, then sprinkle the cheese over the corn.
Transfer the frying pan to the top shelf of the oven and grill for 5–8 minutes or until the cheese has melted and turned golden brown in places.
Remove from the oven and sprinkle with a little cayenne pepper, if using.
Rest for 5 minutes and serve hot, with a cold beer.
