Sift
the flour, confectioners' sugar, and salt into a
large bowl. Use a pastry blender to cut in the
butter until the mixture resembles fine crumbs.
Add the whole egg to form a stiff dough. Divide
the dough in half. Press each half into a disk, wrap
in plastic wrap, and refrigerate for 30 minutes.
Preheat the oven to 400°F/200°C/gas 6. Butter
four cookie sheets. Roll out one disk on a lightly
floured surface to a thickness of 1/8 inch (3 mm)
and to a 14 x 12-inch (35 x 30-cm) rectangle.
Sprinkle with the currants. Roll out the remaining
dough to the same dimensions and place on top of the
currants, pressing down lightly.
Cut into 2 x
1 1/2 inch (5 x 4-cm) strips. Use a spatula to
transfer the cookies to the prepared cookie sheets,
placing them 1 inch (2.5 cm) apart.
Brush with the
remaining beaten egg yolk. Bake, one sheet at a
time, for 10-12 minutes, or until golden brown. Transfer to racks to cool.