I've been to 2 of them here:
Iron Barley, St. Louis - spectacular food, all cooked on cast iron. I really enjoyed my schnitzel and spaetzle, along with the cask beer they always have. It can be exceptionally hard to get a table though, as it's a small place.
Sweetie Pie's, St. Louis - soul food like crazy. It's served cafeteria style, so you pick what you want and they dish it onto your tray. Maybe $10 for a full meal of extremely filling soul food.
I'd recommend either if you're ever here in St. Louis.