As you can see from my avatar, I am Cornish and can trace my roots back to 14th Century... Therefore I am an authority on Cornish pasties...
As others have said, the recipe is for cubed beef, potato, swede (VERY important) and onion. To be fair for the only time to Ginsters, they do actually dice their beef BUT... the pieces are about 2mm by 2mm max, and differentiating it from mince is nigh impossible. Additionally, they lace them with way too much pepper, and there is insufficient swede, so that the finished pasty is dry inside. A properly cooked pasty (and there are many specialist shops available on the High Street) is juicy, because the swede and beef release fat and water which forms the gravy.
I still make them to my mother's recipe, although because of the calories it's rare (like once every 3-4 years) and they are much smaller than she would have made (a proper pasty is a complete meal after which you need a sleep, and has to overhang a dinner plate by 2-3" each side).
In my final years at school (we lived very close), we had combined lessons for Physics with the sister girls' school, and with only a 40 minute effective break, I could get home, pick up the pasty (thoroughly wrapped) take it back for the lesson and make everyone's mouth water with the smell...