Butter the bread slices and spread chutney on 4 slices and mayonnaise to the other 4 slices (unbuttered sides).
Stack the 4 chutney slices with biltong, cheese, onion and tomato. Salt and pepper generously.
Close the sandwiches with the remaining 4 slices.
Place 1 sandwich at a time in your jaffle iron, close and cook on both sides over the braai or a hot plate, until browned to your liking.