Put the cream, 50g sugar and orange zest in a saucepan and bring to the boil, stirring to dissolve the sugar; about 3-4 mins. When dissolved, remove from the heat and stir in the coconut milk.
Put the gelatine leaves in a bowl and cover with cold water. Sit for 5 mins until very soft. Remove the gelatine, squeeze out the excess water and stir into the coconut cream until completely dissolved.
Very lightly grease 4 x 175ml ramekins or dariole moulds with sunflower oil and place on a tray or flat plate. Pour the mixture into the ramekins or moulds and place in the fridge for about 2 hours until just set.
Meanwhile, heat the remaining sugar in a small frying pan. Slice the pith from 1 orange, cut the flesh into round slices and add to the sugar. Cook for 1 min until caramelised, then turn and cook for another min. Serve with the pannacottas, drizzling over the remaining caramel.
Cook's tip: Add a little more drama and tartness to this divine dessert by making it with blood oranges. They have a very short season (January-March), so catch them while you can.