Pre-heat oven to 180° c.Put 100g margarine and 50g sugar into a bowl and cream it. Add 100g of flour and ½ a teaspoon of Vanilla essence into the mixture and mix to form a stiff dough.
Do the same with the other ingredients (in a separate bowl), only add the cocoa.
Now, with the two separate mixtures, take the first one, and roll it out onto a floured surface. Roll it to a 5mm thickness.
Put the second mixture (the cocoa one) on top, and roll it out to relatively the same shape. You now have two different coloured layers.
Take the longest side of the dough and roll it so that the dough now forms a cylinder shape with a spiral visible on either end.
Cut the dough vertically into 16 pieces and lay them on a baking tray that is lined with greased greaseproof paper.
Put in the oven for 15 minutes and take out when they are golden and still slightly soft, as they will set hard.