"Prawn rolls are found at every tourist trap in Maine - every roll is different," says Wall. "We substituted the celery salt some shacks use with pickled celery to offer brightness to a rich roll. Potato chips offer a textural contrast and are the king of American sandwich garnishes. These homemade potato chips are infinitely better than shop-bought brands - maybe some of the guilt of eating potato chips can be offset by knowing you made them yourself." Begin this recipe a day ahead to pickle the celery.