Straccetti di manzo, which translates roughly from the Italian to “little rags of beef,” is a trattoria staple. The cooking is minimal and quick, making this ideal for a weeknight dinner, but the beef must be thinly sliced. In this recipe from our cookbook “ Milk Street Backroads Italy,” we freeze the meat for about 20 minutes to firm it a bit, which allows a knife to glide through the grain.