The restaurant's blues-bar theme is, frankly, a little silly, particularly since the place looks way too new and clean to be in any way authentic. This is, by the way, absolutely fine with the clientele, who, at least based on a sample observed last Saturday night, appears to be comprised of Portage Park residents in their mid-30s who just want a place where they can take their toddlers and still get a decent meal and, therefore, have sacrificed their need for authenticity for clean floors.
On these terms, Leadbelly more than delivers. There's even room to bring the stroller. And, as an extra bonus, the four flat-screen TVs don't play concert films of Leadbelly or of any other blues artists, but U2, which, for many people in their mid-30s, evokes their happy and unencumbered college years when they could eat an enormous burger and not feel bad about it. (God damn, I feel old now. OK. Moving on.)
So about that House of the Rising Sun burger.
It's totally awesome. You may think a patty made up of a mixture of ground beef and smoked pork belly would be overkill, and you'd be right. But it cooks up rich and juicy, with a tinge of spiciness, and it's that rare burger that you might actually want to eat straight up. "Rare" in the sense of "doesn't happen very open" not in "barely cooked, with a red and bloody interior." All Leadbelly burgers are cooked medium as a matter of course, which is their one flaw if you happen to like your meat medium-rare. (Or well done, for that matter.)
There is one problem with all this richness (besides the obvious question of how you can get it into your mouth if you don't happen to have a flexible jaw like a python's): afterwards, it all sits very heavily in your stomach (which may be another inspiration for the restaurant's name, although it's true a blues singer is way cooler). On the bright side, though, you could probably go a full 24 hours without having to eat anything more taxing than a piece of toast or a cup of consomme.