The best way to understand Southern food is as an umbrella term, referring to "all of the cuisines that are found in the American South," Miller explains by e-mail, whereas "soul is a highly-seasoned, urbanized and somewhat limited repertoire of Southern food associated with African Americans. Cajun is Louisiana's country cooking, while its urban cuisine is what we call Creole cuisine."
While there is plenty of overlap, look for iconic dishes such as fried chicken, catfish, greens, black-eyed peas, candied sweet potatoes, biscuits, grits, cornbread and sweet tea at Southern restaurants. Any Cajun spot worth its salt should serve jambalaya, crawfish etouffee, boudin and duck and sausage gumbo, made with both roux and okra. Tabasco is common, and Miller gives "bonus points for alligator." Gumbo is also part of the Creole heritage, made with either seafood or chicken and Andouille, as are red beans and rice, grillades and grits, beignets and bread pudding.
According to Miller, when you walk into a soul-food restaurant you'll probably find the likes of fried or smothered chicken, pork chops, variety meats (such as neckbones, ox tails or pig's ears and feet) with rice and gravy, fried fish, red drink and sweet potato pie, though greens, black-eyed peas, hot water cornbread, macaroni and cheese, candied yams and chitterlings are also common.
Fried chicken transcends all categories, he says, though it's "integral to Southern and soul." For more appetite-whetting discussion, check out Miller's lists of the best soul food and Southern spots in town.