Grease a 20cm square cake tin and line the base with baking paper.
Put the evaporated milk, full cream milk, sugar and marshmallows in a deep saucepan over a low heat. Stir continuously until the sugar has dissolved and the marshmallows have melted.
Bring the mixture to the boil. Allow to boil for 12 minutes, stirring continuously until the mixture has reached soft ball stage. To test this, simply drop a small amount of syrup into a bowl of ice water. If you are able to roll the syrup into a soft ball then you are good to go!
Take the pot off the heat. Add the dark chocolate, butter and vanilla extract and mix well until the butter and chocolate have melted. Mix in the chopped macadamias, almonds and cranberries.
Working quickly, tip the mixture into the prepared tin. Use a spatula to gently flatten the top, (it does not have to be completely smooth).
Pop the tin into the fridge for 3-4 hours until firm. Cut the fudge into blocks and store in an airtight container in the fridge. The fudge will firm up even further overnight.