Meat For the quick gourmet chef, meat is sometimes a problem — so many of the most delicious dishes seem to require hours of simmering time. When minutes matter, it often seems that meat is limited to lamb chops and steak, and as anyone knows who has tried it, it is possible to become jaded with filet mignon six nights in a row. While steak is the greatest quick-cooking meat, there are others, and a real gourmet enjoys all of them. But first comes the steak, and a perfectly cooked steak depends upon three things: thickness of meat, true heat of the broiler, and your personal taste.  Real gourmets eat their steaks rare to blood-rare; well-done beef is only for pot roasts.  Many supposedly-tender cuts such as sirloin and porterhouse can be made foolproof by an unseasoned meat tenderizer—to be sprinkled on and rubbed in about half an hour before cooking. This will not be necessary if you are lucky enough to have a butcher who hangs his own meat; very few do—and when they do, you pay accordingly. Nothing is more critical than steak cookery because split seconds matter. A general rule for a 1-inch steak is: a 500 broiler, meat placed one inch below flame, broil 5 minutes on one side; turn over and broil 3 minutes on the other side.  Remove steak immediately; a steak is one dish that cannot be "kept hot," for every extra minute of heat will destroy the perfect degree of done-ness for your taste.  Personal experimentation will be necessary for steaks, however: perhaps yours is a gas-fired broiler and the thermostat may be slightly off; or your personal taste may be for more red than pink (or vice versa). Armed with a kitchen timer, you must define the exact number of minutes for the exact thickness of steak to produce the result you like best.  FILET MIGNON, TOURNEDOS and CHATEAUBRIAND These are all prime beef tenderloin, differing only in size and presentation. Beef tenderloin needs nothing but a session beneath a broiler flame—but responds to many sauces and marinades.  Filet Mignon is a slice of tenderloin, and absolutely its own excuse for its price. It should be cut 1/2 to an inch thick, weigh about half a pound per serving, and it should not be trimmed of whatever fat it possesses. A filet mignon is always broiled. Tournedos are created by trimming and shaping the entire beef tenderloin into a long roll, wrapped in bacon strips or thin slabs of beef suet, securely tied in place. The Tournedos are then sliced evenly to your order in thicknesses of one or two inches. Customarily they are sauteed in butter or olive oil, and served with fancy sauces and garnishes. Chateaubriand is a thick hunk of beef tenderloin in one piece, weighing one or two pounds. It is grilled or sauteed  before slicing into serving portions. Expensive to buy in a restaurant, it's none too cheap to prepare at home—because the risk of failure is high. A true Chateaubriand must be well-browned but not charred on the outside; pinkish-red and warmed through, yet not raw at the center . . . and this ain't easyl