1. Fill a heatproof glass with hot water and leave to stand. Whip the cream until it forms ribbons underneath the whisk then put back in the fridge.
2. Dissolve the sugar in two tablespoons of hot water in a small pan and bring to the boil. It should go syrupy almost immediately. Take the sugar off the heat and stir in the whiskey.
3. Empty the glass and pour the sweetened whiskey into the bottom, then stir in the coffee. Take the cream out of the fridge, whisk once, then pour it on over the back of a spoon (this helps to stop it sinking). Add a little nutmeg over the top and serve immediately.