Place the dark chocolate and cream in a heat-proof bowl and set it on top of a pan of gently simmering water.
Stir regularly until it is melted and smooth (don't let the base of the bowl touch the water and don't let it get too hot.)
Once it is melted, remove from the heat and stir in the glucose, mixed spice and cinnamon then the dried fruit. Cover and refrigerate until firm.
Roll the chilled ganache into small balls, placing them on a tray as you go. I used about a teaspoon per truffle. Return the truffles to the fridge until cold and firm.
Once the truffles are chilled temper your milk chocolate for dipping. Place two thirds of the chopped chocolate in a heat proof bowl over a pan of gently simmering water, don't let the base of the bowl touch the water. Chop the remaining third of the chocolate very finely, it should be pretty much rubble, set aside.
Heat the chocolate in the bowl over the pan while stirring until the chocolate has melted and reaches 45-50°C. Remove the bowl from the pan and stir in the reserved chocolate. Keep stirring until it reaches 27-28°C. Return the bowl to on top of the pan and keep stirring until it reaches 30-31°C; it is now ready to use.
Dip the truffles into the tempered chocolate one by one using a fork then place them on a tray lined with baking parchment. Any leftover chocolate can be poured onto a piece of baking parchment, left to set then re-used another time, don't throw it away!
Once the truffles have set, melt the white chocolate, either in short burst in the microwave or over a pan of simmering water (I don't bother tempering the white chocolate as it is such a small amount).
Place the white chocolate in a disposable piping bag and snip off just the very tip of the bag. Pipe crosses on top of the truffles and leave to set. I find that you get neater crosses if you move your hand quickly rather than trying to pipe slowly.
Store the truffles in an airtight container in the fridge and consume within three weeks.