Short: Get the Mushroom Burger
Longer: Man, that mushroom burger is so damn good. Been there 3 times now and haven't been able to try anything else because I keep craving that burger. I'm also a sucker for truffle and it's got some truffle oil in there. It's an overall juicy burger too. Definitely a fan of this place. Service is what you would expect at a fast food restaurant. I guess this might be borderline fast casual though since they bring you your burger.
I'm a big garlic fan, but don't like rosemary at all so keep that in mind if you're like me and consider skipping their specialty smash fries. The regular ones are good and crisp.