Lightly grease and fully line 20cm (8in) square cake tin.
Place 400ml (14floz) double cream, 100 ml (3½ floz) milk, 150g (5oz) butter and 300g (10½oz) each of golden caster sugar and light muscovado into a heavy based pan.
Heat gently stirring with a wooden spoon until the butter has melted and the sugars have dissolved
Now increase the heat and boil the fudge mixture, stirring constantly until it reaches 118°C (244°F).
Once the required temperature has been reached, remove the pan from the heat and set aside to cool down to 110°C (230°F). This will only take a couple of minutes.
Add the Whisky to the pan. Be aware that the fudge will bubble up when the whisky is added and beat well.
Continue beating the mixture until it is no longer shiny and begins to thicken.
Pour the whisky fudge mixture into the prepared tin and spread level.
Set aside to cool at room temperature for at least three hours to firm up.
Once set lift the fudge out of the tin and use a sharp knife to slice the fudge into bite sized pieces. Enjoy!