Consumer demand for "more interesting alternatives to everyday biscuits" prompted the company to replace sugar syrup with golden syrup, which provided a more homebaked taste, said marketing director Jaspal Chada.
The packaging now features more images of the cookies and has a lighter background to create a more contemporary feel.
Rolling out across the trade now, the range is priced 89p per pack. The campaign kicked off this week with new TV ads featuring brand characters Cookie Guy and Nigel with the strapline 'Choc Full of Yumminess'. It runs until October on national TV across ITV, Channel 4, Five and satellite channels.