You're probably smelling the Chuck Box, it's really close to city hall. They cook everything over Mesquite.
For a hamburger shop, The Chuck Box is well worth the commute! As has been posted, they cook everything over mesquite charcoal. It is kind of a "build your own" place. You get the burger with cheese or not, on a toasted bun, then you go to the topping bar, and do the rest yourself.
One of my favourite burger joints.
(Now, If Jimmy Buffett's place in Glendale, would cook over charcoal, and put the right cheese, Munster, on their "Cheeseburger in Paradise," they would rate higher in my book.)
steve