Ropa vieja is considered the national dish of Cuba, though its name—meaning “old clothes”—might not exactly hint at just how delicious it is. The name comes from the tomato-based stew’s shredded meat, which bears some resemblance to the tattered edges of worn fabric. The legend attached to it is of a poor old man struggling to feed his family. He used his threadbare clothes in a desperate stew and prayed over the meal. Then a miracle happened: Old clothes became hearty meat stew. A couple of weeks ago, a failure with a crockpot had me digging around for my own miracle. I bought a cheap chunk of meat, top round—not exactly known for its tender qualities. I put it on low heat and, though I gave it several hours, it ended up dried out and tough. It occurred to me that I might save the meat by shredding it up …