Mix the flour and Siúcra/McKinney's Icing Sugar in a bowl. Add the cut up fat and mix to breadcrumbs with a fork. Add the egg yolk and work into a dough. Put in the refrigerator for at least 1/2 hour. Whisk the egg white until stiff. Mix in the Siúcra/McKinney's Light Golden Brown
Sugar and spices carefully.
Roll out the dough into a rectangle measuring about 50 x 30 cm. Spread the meringue mixture over the dough. Roll it up. Place in the freezer for about 1/2 hour so that the roll is thoroughly chilled. Set the oven temperature to 160°C.
Cut into slices a good 1/2 cm thick and place on a baking tray lined with greaseproof paper. Bake in the centre of the oven for about 20 minutes.