Two places...
One is a 'Nati institution. Izzy's, named after a guy named Izzy Kadetz who opened a deli here in 1901…and for nearly 70 years he sold his amazing Rueben and potato pancakes, while he insulted nearly everyone in line. He was the Soup Nazi, before there was a Soup Nazi. Of course it was in good natured fun, and people would actually feel honored if he picked on them. He died years ago, but his place still churns out the finest reuben in the world in the form of a local chain. The finest ingredients, homemade kosher dill pickles and that potato pancake. I could eat it every day. Try to limit myself to monthly visits instead.
Tom+Chee. Another newer local place that serves, you guessed it, only tomato soup and grilled cheese sandwiches in various incarnations. They're getting ready to go national.
Yummmy!!