Sift the flour into a large mixing bowl. Cut in the butter and add sugar, almonds and cocoa powder. Make a well in the middle and add the egg. Knead with your hands, until a stiff dough forms. Roll it into 2 logs with a diameter of about 4cm. Wrap in cling film and chill for a few hours. If you don't have the time, place the dough in the freezer and chill for 30 minutes.
Preheat the oven to 175 C /Gas 3/4 and line a baking tin with baking parchment.
Cut the dough into 5mm thick slices and place the slices on the prepared baking tin.
Bake for 20 minutes or until firm. Remove from the oven and allow to cool on a wire rack before enjoying.