What makes a hot cross bun a hot cross bun? Is it in the bun: the spice, the dried fruit and citrus peel, or even the type of dough? Is it the way you eat it – hot! – sliced in half, toasted and dripping with butter? Or is it the cross itself? Hot cross bun purists will tell you that it’s all of the above, and that any deviation from the classic is, well, deviant.