The investment is part of a wider £55m plan to create state-of-the-art manufacturing facilities across its factories and support key customer Marks & Spencer.
The £3.5bn-turnover group’s meal services division produces own-label products including ready meals and soups and sauces for M&S.
Simon Wookey, divisional managing director at 2 Sisters Food Group told The Yorkshire Post: “It’s all about innovation, particularly with Marks & Spencer.
“They lead the ready meals market and they do so by a very, very active new product development programme.
“Pennine Foods in Sheffield is an extremely flexible factory in terms of pioneering new cuisines. That’s one reason why we decided to continue to invest in this site because we have 800 employees and a lot have been there for quite some time.
“Our customer likes the skill set they bring. That was fundamental in the decision we have taken.”
The majority of the investment will be used to completely rebuild Pennine, with the remainder being allocated to refurbish and expand capacity at 2 Sisters’ factories in South Wales and Carlisle.
Pennine is a purpose-built site, originally established in 1986, which has now reached full capacity. 2 Sisters bought the factory as part of Mr Boparan’s £342m acquisition of Northern Foods in 2011.
The group said the £38m rebuild will develop best-in-class commercial and operational processes to support continued innovation, expand capacity and drive further profitability.
It added that the strengthened operational platform will enable 2 Sisters to continue to grow its position as the market leader in ready meals production in the UK.
Paul Willgoss, director of food technology at Marks & Spencer, said: “This is a significant investment by a key supplier.
“It supports our growth plans and will help us continue to deliver the highest quality and innovation in our products.”
2 Sisters is one of the largest food producers in Europe and supplies customers including Aldi, Asda, Co-op, KFC, Lidl, Morrisons, Sainsbury’s, Tesco and Waitrose.
It has 23,000 employees drawn from 36 nationalities.
Man behind 2 Sisters
Ranjit Boparan has an eye for a tasty deal.
The Birmingham-based entrepreneur made headlines when he gatecrashed Northern Foods’ merger with Ireland’s Greencore just before Christmas 2010, presenting investors with a very appetising offer – the possibility of hard cash.
He sealed the deal in 2011 and vowed to create a £3bn turnover business by 2015.
The 2 Sisters Food Group reported total sales of £3.419bn in the year ending August 2014.
Mr Boparan and his wife Baljinder are the sole shareholders.
The group’s long-term funding includes senior notes nearing £800m.