Grease a baking sheet.
Mix together the chocolate, hazelnuts and raisins.
Unfold the pastry sheets on a lightly floured surface, then put one in front of you (covering the others with clingfilm) and brush with a little of the melted butter. Place a second sheet on top. Cut the pastry into 12 x 6 cm (5 x 2½ inch) rectangles.
Sprinkle a heaped teaspoonful of the chocolate mixture in a line down the long edge of one strip, leaving a 1 cm (½ inch) area uncovered at either end. Fold the ends over the chocolate, then roll up, starting from the chocolate-covered side. Shape the remainder in the same way using the other sheets of filo, so that you have 22 in all. Brush the pastries with more butter.
Bake in a preheated oven, 220°C (425°F), Gas Mark 7, for about 10 minutes until deep golden.
Mix the sugar with the cinnamon and place on a plate. Roll the warm pastries in the spiced sugar until coated. Serve warm or transfer to a wire rack to cool.