Beetlejuice Cookies

For the vanilla dough:

1. Add the butter and icing sugar to a bowl and beat until soft and combined. Whisk the flour, cornstarch and salt in a bowl, then gradually beat it into the butter mixture. Set aside.

For the chocolate dough:

1. Add the butter and icing sugar to a bowl and beat until soft and combined. Whisk the flour, black cocoa powder, cornstarch and salt in a bowl, then gradually beat it into the butter mixture. Set aside.

To assemble

1. Roll the chocolate dough between two pieces of wax paper or baking parchment paper in a square about ⅛-inch thick. Place onto a cookie sheet in the papers.
2. Repeat with the vanilla flavour, in the same shape and thickness, then stack it (in its paper) on top of the chocolate flavour. Place in the fridge for 15 minutes.
3. Remove the top layer of paper from the vanilla square of dough, and brush with some of the beaten egg white. Place the chocolate dough on top (without its wax paper).
4. Trim the edges of the stack, so the sides are all straight.
5. Cut the dough into 6 equal-width strips.
6. Brush four of the six strips with egg white and stack them on top of each other. You should end up with two long, narrow stacks, each consisting of three strips of white dough and three strips of black dough, alternating between the two colors.
7. Place them onto the baking tray (ensuring they won’t fall over) and chill for a further 15 minutes to firm up a little.
8. Preheat the oven to 400°F/200°C. Line two cookie sheets with parchment paper.
9. Cut the dough into ¼-inch thick striped slices. Place each one onto the cookie sheet, leaving space for them to rise.
10. Bake for 8 minutes or until the edges just begin to turn golden. Leave them on the cookie sheet for 5 minutes, then transfer to a wire rack to cool completely.