Strong demand for Croissant Donuts has prompted Dunkin’ Donuts to extend the availability of the flaky croissant rings glazed like a donut into 2015. The bakery-cafe said it has sold more than 4.6 million of the baked goods since introducing the limited-time offering in November. Dunkin’ said the positive response from guests has made the Croissant Donut one of the most popular limited-time bakery items in recent brand history. “The positive customer response to our Croissant Donut reflects the success of our strategies focused on providing guests a menu that offers a combination of old favorites like our Original Blend Coffee and innovative and fun new products like the Croissant Donut,” said  John Costello, president of global marketing and innovation for Dunkin’ Brands. “We are thrilled to extend the availability of the Croissant Donut into 2015 based on popular demand.”