Heat the oven to 180°C /350°F.

Mix all the dry ingredients, except the cocoa powder, together.  If you cannot find almond meal, grind up whole, peeled almonds in a blender until you have a fine mix and use those.

Add the butter and work it into the dry ingredients using either a standing mix or your hands.

Separate the dough into two roughly equals portions and add the cocoa powder to one of the balls. Knead it into the dough.

Break off small pieces of the dough and roll it into balls.  Place them on a cookie-tray lined with baking paper.Push the balls down gently so that a flat bottom forms.

Bake for 15 minutes, then leave to cool for at least 1 hour.

Melt the chocolate over a very low heat. Spread some of the chocolate on the flat side of one cookie and stick it to another one about the same size. Put them gently on a tray covered in baking paper and leave them to set.