First of all I actually laughed out loud at how small the burger was. I'm still astonished by how small it is. I did ask if they had a mushroom burger and was told no, but they could put mushrooms on a burger. Then I read that on the secret menu the first burger listed is a mushroom burger, but that is for "regular" customers. You've only been open three days. How many regular customers do you have???
The burger is two thin, over cooked patties. The bun is very fresh but has no flavor and as far as the mushrooms go, well on this tiny burger they are barely noticeable.
The onion rings are good. Nice to be able to have a beer
Kinda slow service however. No real heed to return.