^^^ Yorkshire pudding can be a starter, an accompaniment to a main course or a dessert, Sanmac.
In most of the UK, it's served alongside a main course (often, but not necessarily, including a roast meat). However in some parts of Yorkshire it's served as a starter, simply with a thick rich onion gravy. In some parts of Scotland though, it's served as a dessert, with custard!
Half a century ago, in my college days, I had a mate who lived midway between Huddersfield and Halifax, in the heart of Yorkshire. When his family had Yorkshire pudding, his father ate his as a starter, my mate ate his with his main course and his Glaswegian mother had hers with custard afterwards!
In proper, old-fashioned Yorkshire pubs (such as many around Rotherham), the landlady cooks a massive Yorkshire pudding each Sunday lunchtime, which is passed around the bar so that customers can rip large pieces off with their hands (totally ignoring any hygiene considerations!) and dunk them in the big bowl of gravy that's passed around at the same time. It goes superbly with a pint of Yorkshire ale ;-)