Combine in a bowl hazelnuts, almonds and sifted flour; stir until well mixed.
Place egg whites in a small bowl of electric mixer, beat until egg whites are frothy, add sugar and continue beating 3 minutes on full speed.
Fold in the nut-flour mixture.
Spoon mixture into piping bag fitted with 2cm (3/4 inch) wide plain tube. Pipe 8cm (3 inch) long sticks on lightly greased oven trays. Alternatively, roll out sticks according to preferred size.
Bake in moderately slow oven 12 to 15 minutes.
Remove from trays and cool on wire rack.
Melt chopped chocolate in a saucepan over simmering water.
Remove from heat.
Dip sticks into chocolate ¾ of the way down the biscuit and place on aluminium foil until set.