But the owner of a small chain of local bakeries, Bea's of Bloomsbury, has hit out after the coffee chain trademarked the name of one of her most popular products.
A sign at Bea's of Bloomsbury
Bea Vo claims that she devised her version of the duffin more than two years ago and has been selling the pastry in her four London-based cafés since.
Her recipe, which includes nutmeg and buttermilk and is injected with raspberry jam, was also included in her cookbook, Tea With Bea, published in September 2011.
Bea told the Huffington Post UK that Starbucks was "attempting to take over rights of something they didn't create or really own.
"It's like someone trying to trademark 'fairy cakes' or 'whoopie pies' or 'macarons'", she said.
The duffin, which was last week trademarked by Starbucks UK
"Duffins have been in existence for years and they are trying to trademark something that has been in the baking lexicon documented for at least two years."
Foodies have taken to Twitter in support of the baker and café owner, using the terms "#duffin" and "#duffingate" to whip up a storm.
Starbucks, meanwhile, calls its duffin "lightly spiced with nutmeg", with "a raspberry jam filling and a buttery sugar coating".
The coffee chain, which launched the sweet treat at 730 branches across the UK last week, described the duffin as the "perfect creation".