Well, if you are from the Atchafalaya basin, you would need a large spoonful of potato salad sitting on top, or if not, a nice piece (think large) of buttered french bread and you are good to go.
The cafeteria where I retired from hired a chef/manager who was a Cajun and he would make Gumbo Boats and Etouffee Boats. They took French Bread, cut in half, hollowed out then filled with which ever filling they made that week. You had to be early to get some at first, then they found out they could sell any leftovers the next day. It was a sad day when he moved on to another place.