A currant bun is a sweet bun that contains currants or raisins.The Chelsea bun is a variant. Neither should be confused with a spiced bun, nor with a similar cake called the tea cake. Nor should it be confused with the scone, a form of cake that is also likely to use currants but which is generally smaller, and which is usually eaten with butter or some butter substitute.Currant Bun is English rhyming slang for the tabloid newspaper The Sun.