Melt the butter in a heavy based saucepan, over a medium heat.
Add the sugar and cream and stir until the sugar has melted.
Turn the heat up until the mixture boils, and boil for around 20 minutes, or until a sugar thermometer indicates a soft crack stage. Stir frequently.
Remove from the heat and beat in the white chocolate.
Leave to cool for 5 minutes, then split 1/3 of the mixture away from the main mix.
To the smaller section, add food colouring until desired colour is reached.
To the larger section add the cranberries and mix thoroughly.
Assemble your moulds, with the smaller heart inside the larger tin. The smaller, insert mould should be greased on both sides.
Pour the cranberry mix into the outer mould, and the red fudge into the centre.
Leave to cool for around 1 hour, then remove the central insert shape.
Chill in the fridge for at least 2 hours, preferably overnight.
If you have a flat mould, your fudge is ready to turn out.
If you have a loaf mould you will need to cut your 'loaf' into slabs. Ideally you would do this with cheese wire, but this is difficult to get hold of. Fortunately dental floss works well too!