We're forever scouring thrift stores and yard sales for Griswold pans: skillets in dozens of shapes and sizes; cake molds resembling lambs and rabbits; pans designed for heart-shaped muffins. Until the Erie, Pennsylvania-based company shut down its foundry in 1957, it used an unusually fine sand as a base and employed hand-finishing techniques that produced some of the most beautiful and stick-proof cast-iron cooking pieces ever made.