1. Roughly chop all the chocolate into smallish chunks.
2. Combine the butter and Tate & Lyle Light Muscovado Sugar together in a mixing bowl and, using a wooden spoon, beat until light and creamy for 2-3 minutes. Mix in the egg and vanilla and scrape down the sides of the bowl.
3. Next, sift together the flour, bicarbonate of soda, baking powder and salt then stir into the creamed mixture to make a soft dough.
4. Add the chocolate and nuts and mix through. Divide into 16, roll into balls, place on a tray, cover with cling film and chill for 30 minutes.
5. Preheat the oven to 180°C/Fan160°C, 350F, Gas Mark 4.
6. Place 3 or 4 balls of dough on each baking tray, well spaced apart as they will spread. Bake on the top and middle shelves of the oven for 20-22 minutes, swapping the trays over halfway through. They are ready when pale golden and still a little soft. Leave to firm up on the trays before removing with a palette knife to a wire rack to cool, then bake the rest of the cookies. Serve.

You will also need 2 baking trays lined with parchment paper.