They're based on Mary Berry's fork biscuits from her Ultimate Cake Book which is my baking bible (much more useful and reliable than Domestic Goddess).
This is the recipe with my adaptations in bold.
Makes 32 biscuits
8 oz (230g) soft butter
4 oz (115g) caster sugar I substituted dark soft brown sugar
9 oz (250g) self-raising flour
1 oz (30g) cocoa powder
½ teaspoon ground cayenne
½ teaspoon ground cinnamon
½ teaspoon ground ginger
¼ teaspoon ground cloves
6 oz (170g) plain chocolate chips
Beat the butter and sugar together by hand or with electric beaters until well combined.
Add the flour, cocoa powder and spices and mix into the butter-sugar mixture. I do this with electric beaters, it looks wrong to begin with as the mixture is a floury, crumby mess but keep going and the crumbs will become less floury and more like biscuit dough.
Add the chocolate chips, work them into the dough with your hands and bring together into a ball.
Make walnut sized balls of dough, place them on baking trays which you have greased or lined with reusable baking liners. squash each ball of dough down a bit with your hand or a fork.
Bake for 20 minutes at 180°c (160°c fan oven).
Allow to cool for a few minutes on the trays before lifting off with a palette knife to cool and get crisp on a cooling rack.