There's a new place at the City Creek mall, recently voted the best mall in America. (I also didn't realize it was possible to be voted the best mall after 1992, but I stand corrected).
My coworker really wanted to go to Johnny Rockets, mostly because I think she wanted an Oreo shake (yeah, not gluten free). I decided to join her. The Johnny Rockets website gives allergen information, and there are reviews online that you can order a bunless hamburger that will be safely prepared. Johnny Rockets restaurants fry other things beside fries in their fryers, which doesn't meet my gluten free standards, so I didn't order any of those. I did order a salad instead, which was essentially the hamburger toppings of lettuce and tomato, and some cheese I needed to pick off.
You can see that the cheese came in handy.
The meal was successfully gluten free, and our server was knowledgeable enough to help out. I definitely appreciated that. From a more practical view, the food was more expensive for a meal that included extra hamburger toppings as a salad. Still, it's a family friendly option at City Creek where you are likely to get a safely prepared gluten free hamburger that doesn't seem to have cross contamination issues.
City Creek Center, downtown Salt Lake City
Food Court, 2nd floor (northeast corner)