To make the cake truffles, place all the ingredients into a bowl and mix together with a large spoon until the mixture comes together. Line a tray with non-stick baking paper. Roll 2 teaspoonfuls of cake mixture into a ball. Place on the prepared tray. Repeat with remaining cake mixture. Place in the fridge for 30 minutes or until firm. Next, place the truffles into small paper cases and place on a serving tray. Spoon the melted white chocolate into a piping bag or a small sealable plastic bag and use to drizzle over the top of the truffles. Quickly place a marzipan holly cut out onto each truffle and allow to set before serving.