One of the rules of stir-frying (see A Stir-Fry Education) is that ingredients must be cut into precisely uniform pieces so that they cook evenly in the wok. As hard as we tried, though, we couldn't achieve the thin, perfectly even slices of meat called for in the recipes for stir-fried pork with leeks (see Stir-Fried Pork with Leeks) and stir-fried chicken with celery (see Stir-Fried Chicken with Celery). Invariably, when we sliced the meats, we ended up with a few too-thick pieces, which tended to undercook, and some too-thin ones, which got overcooked and chewy. Knowing that we wouldn't be able to apprentice for months with master stir-fry cooks, we came up with a different solution. Just as it's easier to slice a firm cheese than a soft one, we figured, so it must be with meat. So, we chilled the chicken and pork in the freezer for 20 minutes—just long enough to firm it up—making consistent slicing a breeze.