In a small bowl, combine the currants and liqueur. Set aside.

Combine the flour, half the sugar and salt in a medium bowl. Whisk together.

Use a fork to mix through the milk, then pull the dough together with your hands.

Flatten out into a rectangle. Wrap in baking paper or plastic wrap and chill for 30 minutes.

Drain the currants, discarding the liquid. Set aside in a strainer over a dish to drain further.

In a small bowl, combine the remaining sugar and cinnamon. Set aside.

Cut the dough in half and, on a lightly floured surface, roll out one half to about 20cm square (8x8 inches) - use the base of an 8 inch tin as a guide. Carefully transfer it to the baking tray.

Scatter the drained currants over the rolled dough, followed by half the cinnamon sugar.

Roll out the second piece of dough and lay it over the top. Press down gently all over with your hands and trim off the rough edges of dough.

Brush the top with the egg wash, then sprinkle over the remaining cinnamon sugar.

Bake 25-30 minutes or until the top is nice and golden.

Carefully, use the ends of the baking paper to move the biscuit from the tray to a cutting board. Cut into rectangles, then allow to cool completely.