Take rind and juice from orange, place in mixing bowl
Mix in sugar and cinnamon
Half apples through the middle and remove the core
Toss in the orange mixture
Pour custard into baking dish
Arrange apples, cut side up, on top of custard
Drizzle over any remaining orange juice
Sprinkle over granola
Bake for 20 mins then cover with foil and bake for further 10 mins
Serve with cream or ice cream