Preheat the
oven to 350°F/180°C/gas 4. Line four cookie
sheets with parchment paper.
Sift the
flour, baking powder, and salt into a medium
bowl. Beat the butter and sugar in a large bowl
with an electric mixer at high speed until
creamy.
Add the egg,
beating until just blended. Finely grate 2 oz
(60 g) of the chocolate and beat into the
mixture. Beat in the orange zest.
Mix in the
dry ingredients to form a soft dough. Turn the
dough out onto a lightly floured surface and
knead until smooth.
Form
tablespoons of the dough into 8inch (20-cm)
ropes. Fold in half and twist, pressing the ends
of the rope together.
Transfer to
the prepared cookie sheets, placing them 2
inches (5 cm) apart. Bake, one batch at a time,
for 10-12 minutes, or until just firm. Transfer
to racks to cool.
Melt the
remaining chocolate in a double boiler over
barely simmering water. Dip in the tops of
cookies and let set for 30 minutes.