Ingredients:  
160g/5 ½ oz plain flour
65g/2oz cocoa powder
1 tsp baking soda
¼ tsp baking powder
¼ tsp salt
200g/7oz caster sugar
140g/4 ½ oz butter, cut into pieces
1 egg

Filling:
50g/2 oz Cookeen fat
60g/2 oz butter
250g/9 oz icing sugar
2 tsp vanilla extract

Method:
1. Put the flour, cocoa, baking soda, baking powder, salt and sugar into a food processor and mix together on a low speed. Gradually add the butter and then the egg and continue mixing until the dough comes together. Put the dough into a bowl and refrigerate for 15-30 mins.
2. Preheat the oven to 190°C and line two baking trays with baking paper.
3. Take teaspoons of the dough and roll into little balls in your hand. Put the balls on the lined tray and flatten with moistened fingers. Bake for 9 mins, then leave to cool on the baking tray.
4. To make the filling put the Cookeen and butter in a bowl and beat together, gradually adding the icing sugar and vanilla extract until smooth and creamy.
5. Put the filling into a plastic bag, cut off one corner and pipe it on half on the cookies. Cover with the other half of the cookies and gently press together to work the filling evenly to the outsides of the cookies.