Reduce the heat to low – if the caramel gets too dark, remove it from the heat, but you may need a little heat to keep the caramel liquid enough to dunk. Dip the prepared apples into the caramel, spinning them in the sugar to coat all over. Transfer to the lined tray, then sprinkle over the chopped nuts or seeds, working quickly before the caramel sets. Leave to set for 1 hour until completely hard. Best eaten within a day of making.