We're making two different layers of fudge, so melt half of the butter (15 grams) in a saucepan. Best to do this in a double boiler. You can do it on direct heat as well but make sure the pan doesn't get too hot. Once the butter has melted add the milk chocolate in and let this melt with the butter.
Once the chocolate has melted, add half of the condensed milk can to it. Keep stirring until it is a smooth mix and stir in the chopped small pieces of marzipan.
Use a low baking tray, cover the inside with baking paper. Pour the contents of your pan in the baking tin and spread it evenly across the bottom. Than place it in the fridge for half an hour so the first layer can set while you prepare the second one.
Repeat the process for the second layer but this time use the white chocolate and add the crumbled ginger cookies through it. Pour this on top of the milk chocolate layer and leave to set in the fridge for a few hours.