To make the filling, cream together the
butter and icing sugar until smooth, then stir in the currants. Roll
out the pastry to a rectangle about 40 x 15 cm/ 16 x 6 in. Spread with
the butter filling and sprinkle with cinnamon. Roll up from the short
end to make a Swiss (jelly) roll shape. Cut into 16 slices and place
on a baking (cookie) sheet. Leave in a warm place for 15 minutes. Bake
in a preheated oven at 230°C/450°F/gas mark 8 for 10—15 minutes until
golden. Leave to cool, then decorate with glace icing.