Combining hot mashed potatoes, butter, onions, and breadcrumbs results in a decidedly delicious dish. The genius behind the recipe? George Rector, a famous American restaurateur.
Combine and mix all ingredients except the breadcrumbs and egg. Shape into croquettes. Roll the croquettes in the breadcrumbs, dip in the egg, and roll once again in breadcrumbs.
Fry in deep, hot fat that registers at 375 degrees on a thermometer, until nicely browned. Drain on absorbent paper.