Combine the peanut butter, butter, Tate & Lyle Demerara Sugar, egg, flour, baking powder and chocolate in a bowl and mix with a wooden spoon to make a soft dough.
Divide into 20 even-sized balls and place spaced apart on the baking trays as they spread.
Bake on the middle and top shelves of the oven for 12-15 minutes until golden brown, swapping the trays over halfway through. Leave to cool for a few minutes, then remove to a wire rack to cool completely.
You will also need 2 baking trays lined with parchment paper.
Try not to handle the dough too much as this will make your cookies tougher.