John Besh is an accomplished chef— he has 17 restaurants and has published four cookbooks—but in his home kitchen in Slidell, LA, he’s more of a short-order cook. “In the morning with the boys, this is sort of our diner,” says John, who often whips up simple Southern favorites like grits and biscuits here for his wife, Jenifer, and sons Brendan, 21, Jack, 16, Luke, 15, and Andrew, 13. But come Thanksgiving, the space becomes way more than a diner. John and Jenifer, who both came from big local families, will host 60 people for a massive Big Easy feast this year. John will fire up all four of his Viking ovens to crank out turkeys, crawfish cornbread dressing and, true to Louisiana tradition, a huge pot of gumbo. For…