Double chocolate & sour cherry cookies

1 Using electric beaters or a wooden spoon, cream together the butter and sugars until combined, then add the egg and vanilla extract. Mix together the remaining ingredients in a separate bowl, then add to the butter and sugar mixture; mix briefy to combine. Lay a large sheet of baking parchment out on a work surface; roll the cookie dough mixture into a 30cm-long sausage shape on top, then wrap tightly in the parchment, sealing the ends. Put in a freezer bag, seal and freeze for at least 45 minutes (or up to 1 month).

2 When ready to bake, preheat the oven to 190°C, gas mark 5. Line 2 large baking trays with parchment. Remove the dough from the freezer and bag; allow to sit for a couple of minutes, then use a sharp knife to carefully cut into 1-1½ cm slices. Bake on the lined baking trays, in batches if needed, for 11-12 minutes. Leave on the trays for 5 minutes to cool slightly, then transfer to a wire rack to cool completely.