Spread one slice of bread with the mango chutney. Top with the sliced chilli, a few coriander leaves and red onion. Scatter over the cheddar and top with the other slice of bread, then butter the outsides of the sandwich. Cook in a hot pan, weighed down by another heavy pan, for 2-3 mins on each side until the outside is crisp and the cheese has melted. Alternatively, cook in a sandwich toaster.