I had a few burgers during my time in London, and all the pubs or restaurants seemed to be using a similar burger bun. It was very soft inside and the crust was very fragile, crumbly and flaky ... just holding the burger meant the crust would crumble and tear indentations where your fingers pressed down.
Does anyone know what bun this may have been? Someone mentioned Brioche to me, but I made Brioche in Patisserie class and it had kind of a firm, bound, strong texture. Like it would be a little resistant to tearing, almost as if the crust had some kind of plastic coating for protection (of course it didn't, but you know what I mean).
Also, What would you say are the top 3 burger buns being used today? What country do you live in and what bun is popular there?