Measure the oats into a measuring jug and top up with water to the 500ml or 18 fl oz mark. Leave for 48 hours for the mixture to steep.
Place a sieve over a saucepan and strain the oat water into it.
Juice the oranges and add the juice to the saucepan with the sugar. Bring the mixture to the boil over a medium heat and simmer for about 10 to 15 minutes until the mixture is thick.
Let the custard cool for 5 minutes and then stir in the cream.
Divide between 4 glasses and chill for an hour until set.
Pour over the honey and whiskey.
Whip the cream until it just holds its shape then place in a piping bag fitted with a large star nozzle.