Camille Caubere had a nose for a good thing when she gave Xuxu a deft makeover, the former little canteen tucked away in a peaceful corner of Biarritz. It’s the kind of place that makes it hard to drag yourself away: a sunlit dining room, white-paneled walls, Alki furniture, breakfast on the fly (with Azeria coffee roasted in Anglet), to-die-for pastries, Basque beverages and a tightly edited...