From The Dairy Book of British Food. "These were the poor man's meatless substitute for the real thing, and are today an interesting dish for vegetarians". Caerphilly cheese is a white, crumbly/flaky cheese that is a bit tart. Use a medium to tart cheddar if you can't get Caerphilly cheese. You could substitute a non-British cheese that is a bit tart or salty, from cows! Caerphilly is an old, old castle town in the county of Glamorgan.