The confusion that Yorkshire pudding is not a sweet pudding lies in the understanding that until the mid 17th century the majority of British puddings were savoury. These puddings were similar to sausages with meat forced into a skin then boiled or fried. Or they were boiled puddings cooked in pudding cloths – think steak and kidney pudding.
By the second half of the 18th century traditional English puddings no longer included meat and by the 19th, still boiled though they more resembled cakes. The survivors of the earliest pudding seen in the modern kitchen are black pudding, white pudding and, of course, the haggis.