A saffron bun, Cornish tea treat bun or revel bun, is a rich, spiced yeast-leavened sweet bun that is flavoured with saffron and contains dried fruit including currants and raisins similar to a teacake. The main ingredients are plain flour, butter, yeast, caster sugar, currants and sultanas.[1] Larger versions baked in a loaf tin are known as saffron cake.