2) In a separate bowl, whisk together the flour, bicarbonate of soda and salt. Add the flour mixture to the butter and sugar mixture in batches. Stir with a spatula until well blended. Fold in the chocolate chips or chunks and spoon the dough onto 2 greaseproof paper-lined baking sheets, at least 2.5cm apart.
3) Bake for 14 to 15 minutes. Rotate the baking sheet half way through so that the biscuits bake evenly. Remove the baking tray from the oven and transfer to a wire rack to cool.