I have my shack stack wrapped in lettuce with no bun, but I do love mushrooms. Normally I don't eat anything breaded, but the tiny bit (very thin breading) on the fried, cheese stuffed portobella mushroom is acceptable because I get them so infrequently. There are no Shake Shack in my state, so I at most get to eat there once or twice a year. I also get my shack stack with added bacon (like any self respecting person).