My absolute favorite though has to be Portillos. They make everything so good. I am especially fond of the Italian Beef (hot of course). Just dripping with goodness.
It was my first official Chicago food. After a long day of house hunting with my real estate agent Mike Kwain (Century 21 he is so awesome by the way. You should call him up) he treated me to my first Italian Beef. I was expecting something like a roast beef with au jus but no Portillos has perfected the art of beef, dripping with juices and flavor and the bun is just right. It doesn't matter what time of day I order it it is always perfection. My waistline is suffering but it seems so worth it at the time.
I am fond of Home Run Inn pizza as well because I was there for dinner when I got the call that our offer on the house was accepted.
You can complain about the weather here all you want and you would get absolute agreement from me but you can't complain about the food.

