The agency won the business without a pitch. It previously worked on the Premier Foods cake brand Mr Kipling.
101’s capture of the business sees it return to the Premier Foods roster following last year’s consolidation of all Premier ad accounts into JWT London and McCann London. 101 lost the Mr Kipling account to JWT as part of the process.
Premier is set to spend £2 million supporting the Cadbury brand through a range of media.
The brand hasn’t recently been backed by significant advertising spend. McCann was the last reported agency of record on the brand, having won the business in 2007.
Matt Hunt, the marketing director at Premier Foods, said: "Cadbury Mini Rolls are an iconic product and the single biggest product in the ambient cake category.
"Currently growing ahead of the category, 101 were the obvious choice to help accelerate this – given their previous experience working with Mr Kipling and their knowledge of chocolate confectionery markets."
Last year, Premier Foods extended its licence to produce Cadbury-branded cakes until at least June 2017.