In a mixing bowl, cream together the
butter and sugar until light and fluffy, then gradually beat in the
egg yolk.
Sieve the flour into the creamed mixture
and mix until evenly combined. Add the orange, lemon and lime rinds
and orange juice to make the mixture into a soft dough.
Roll out the dough on a lightly floured
surface. Stamp out rounds using a 7 cm biscuit cutter.
Place the round dough on to the grease
baking trays. Prick the surface with a fork.
Lightly whisk the egg white in a small
bowl and brush it over the biscuits. Dust with icing sugar.
Bake in preheated oven for 12 minutes or
until lightly brown. Leave the biscuits to cool on a wire rack.
