Chocolate truffles

Chocolate truffles ( makes 28 )

200g dark chocolate (60-70% cocoa solids)
1/2 cup cream                                          
100g 70% dark chocolate for enrobing      
Cocoa powder for dusting                           

1. Finely grate the 200g dark chocolate, place in a bowl. Pour the cream into a small pot and bring to just below boiling point. Pour the hot cream over the grated chocolate and stir until all the chocolate has melted.
2. Pour mixture into a small shallow dish and refrigerate until firm. Scoop up some of the truffle mixture using a teaspoon and shape into a ball by rolling between your palms. Repeat until all the truffle mixture has been used up, and refrigerate until firm.
3. chop the remaining 100g chocolate, place in a heat-proof-bowl over a pot of simmering water, making sure the bowl does not touch the water; allow chocolate to melt.
4. place a truffle on a fork and, with a spoon, drizzle melted chocolate over the top, turning the truffle until all excess chocolate has drizzled off. Place on a lined baking tray and refrigerate until set. Repeat with half the truffles.
5. Sprinkle a layer of cocoa powder onto a surface, and roll remaining truffles in the cocoa until well coated. Refrigerate untill ready to serve.