I love mushrooms and have recently tried to do more things with them. These "buns" taste great and they're so easy to make. The Worcestershire sauce works really well.
The recipe can be found here: http://betterfoods.ca/recipes.html
. I read about that company in Erin Davis' blog, for those who know who that is. They make burgers that combine beef and soy that are just fantastic. Really low on fat. I'd recommend trying those too.
I also really liked their plum relish, though the tzatziki wasn't that great - the one that was posted here looks like it might be better.