Tortilla de Patatas

When Vanessa and I were working in a bar in the Pyrenees, the mother of the owner, Aurora, explained to us in her own inimitable manner that there was only one way to make a tortilla and that was her way. She started her tortilla de patatas by holding a potato in one hand and a stubby, yet cruelly sharp, knife in the other then, in a blur of motion, scored the potato one way then the other and, as she did, wafer thin slips of white potato flesh would fall into the pan. She pas