The coffee shop chain, however, was late to the party, as London-based baker Bea's of Bloomsbury had been making muffins with jam in the middle for some time now. And when it discovered that the U.S. firm's plans, it reacted with a Twitter campaign: #duffingateGuess what? Plucky Underdog 1, Large Corp-o-Coffee 0.
Some helpful tweeps are already suggesting Starbucks rename its version the MuffNut, while others are pointing to a brownie-doughnut hybrid, the BroNut.
[Image: Flickr user sleepyneko]