For the truffles place the white chocolate, cream and gingerbread syrup into a heatproof bowl and set over a pan of barely simmering water. Stirring, bring together into a smooth glossy ganache.
Pour the ganache into a small roasting tray lined with baking paper.
Allow the ganache to cool, then pop in the fridge to set - about 4 hours. Whilst the ganache sets, grind the gingernut biscuits into a powder in a food processor then pour into a ziplock plastic bag.
Once the ganache has set, use a teaspoon (or grease-sprayed melon baller) to scrape out small portions of the chocolate.
Roll these into cherry tomato sized truffles, then pop each one into the bag of gingernut crumbs and toss to coat really well. Set the coated truffles onto a baking sheet and pop back into the fridge until needed.
To temper the chocolate melt the chocolate in a heatproof bowl over a pan of barely simmering water. Remove from the heat and wipe the bottom of the bowl to avoid any water coming into contact with the chocolate.
Pour two Thirds of the chocolate onto the clean, dry marble slab and use the palette knife and wallpaper scraper to spread it out thinly, then scrape it back into a pool, about 4 or 5 times or until it starts to thicken a little.
Pour this back into the melted chocolate and stir well to equalise the temperatures.
Dip a teaspoon into the chocolate - if it sets within a minute or so without going grey, the chocolate will be tempered. Working quickly dip each truffle into the tempered chocolate with a fork (or chocolate dipping hook if you have one) and coat well, then place onto a piece of baking paper to set.
To finish, brush a little edible gold lustre dust onto the top of each set truffle.