Chop chocolate and melt it in double boiler set over hot water. I wait until half melted and then start stirring – usually it is enough. Don’t overheat it! Shards will not be crunchy and will look very dull – like chocolate that go bad. If it starts having air bubbles – means it is already overheated.
Place parchment paper (any baking lining paper will do – but NOT foil) on your table. Pour the melted chocolate on the paper and using a spatula or spoon, spread it in a thin and even layer. Leave about 5cm space off the edges. Then cover it with second sheet of same sized parchment paper on top and gently press to even out the thickness. Don’t do it too thin (shards start folding and loose shape if they are 1mm thickness). 2.5-3mm is perfect. Try to leave about 3cm around the edges empty – you do not want chocolate to leak. Starting with one short end, roll the parchment paper tightly into a tube. It is your decision how wide tube you want: 3-6cm. Then lay this tube horizontally in freezer for about an half an hour, or longer, until it gets sturdy.
As you can see, I made them way to thin (I think they were 0.5-1mm).