Pour 250 ml (8.5 fl oz) of milk, 300 g (10.6 oz) of cream and 100 g (3.5 oz) of sugar in a saucepan. Heat on a low flame and, just before the cream comes to the boil, put 9 g (0.32 oz) of gelatine in a container with cold water and leave to soak for about two minutes.
As soon as the cream starts boiling, drain the gelatine and add it to the mix. Stir slowly and turn off the heat.
Add the whisky and stir until you obtain a smooth texture. Take 5 glasses, pour about 100 g (3.5 oz) of the mix in each one, and leave to rest in the refrigerator for about 24 hours.
When the coffee is ready, pour an espresso cup on the cream in each glass. The upside-down Irish coffee is now ready to be served.