A beef tenderloin roast comes from the upper rear portion of the loin, or midsection. Cut from an area of the animal that performs very little exercise, a trimmed tenderloin is nearly gristle-free; it also is quite lean. The full tenderloin roast is shaped like an elongated teardrop: wide and blunt at one end, tapering to a flat, skinny "tail." Some cooks tuck the tail under and tie the roast for a more uniform shape. Others remove the tail and reserve it for another use.
Thin slices of beef tenderloin tail work well in stir-fry, particularly if you like it lean. For a simple stir-fry, slice the tenderloin across the grain into pieces 1/4 inch thick or thinner. Mince a couple of garlic cloves and a 1/2-inch piece of peeled ginger. Cut a few vegetables of your choice -- consider onions, peppers, snow peas, carrots, celery and broccoli -- into thin slices or bite-size pieces.
Heat a small amount of oil in a wok or wide skillet over high heat. Add the tenderloin, garlic and ginger and stir-fry until the tenderloin browns. Remove from heat and reserve the meat. Add a little more oil to the wok as needed and stir-fry the vegetables, starting with the firmest ones and adding softer ones such as pea pods just as the first vegetables start to caramelize. Return the beef to the wok and season with soy sauce, a dash of sesame oil or a commercial stir-fry sauce to taste. Mix well and serve over rice or noodles.
Cut the tenderloin tail into 3/4-inch chunks for use in kabobs. Marinate the meat first, if desired, in a homemade or commercial preparation. For a homemade marinade, combine a few tablespoons of oil with an acid such as wine or vinegar, plus flavor elements like minced garlic or ginger, salt, pepper and herbs. Thread the chunks of tenderloin onto metal or bamboo skewers -- soak the bamboo ones in water for 30 minutes first -- with alternating chunks of vegetables. Grill or broil the skewers using high heat.
Beef Stroganoff is a classic recipe combining beef tenderloin with mushrooms; onions or shallots; red wine or cognac; and sour cream or creme fraiche. A popular dish at 1950s and '60s dinner parties, beef Stroganoff is traditionally served over egg noodles. You can lighten the calorie load of beef Stroganoff by using reduced-fat sour cream or by replacing some of the sour cream called for in a recipe with plain yogurt.
Because beef tenderloin is relatively free of fat and gristle, unlike cuts such as chuck, it will tend to toughen and lose flavor in stews or other recipes that call for long, slow braising. It is possible to grind up a beef tenderloin tail for hamburgers, but burger aficionados generally prefer ground beef from fattier cuts for flavor. You can grill a beef tenderloin tail as a steak so long as it's no more than 1.5 inches thick; keep in mind that its tapered profile will likely result in one end being more well done than the other. Consider wrapping it in bacon for additional flavor.