I think what the OP is looking for is a leisurely meal to kill a big part of a long layover. Pappadeaux is good for that; they won't give you the bum's rush and it is removed from the mad pace of the airport concourse.Try Papas BBQ we usually stop there going home.
It's served fast food style in the airport but they have a chain of BBQ's in and around Houston that are considered pretty good. Sandwich's and BBQ plates . It's located around E14 next to a Wendys and Starbucks.
Great back home meal, cheap and fast.