We've told the story elsewhere about Chateaubriand's chef cooking his master's tenderloin between two other tenderloins, letting them overcook and discarding them, so that the center roast was done perfectly. We assume your finances will also allow for the same approach, so that each of your parents can have well-done tenderloins all to themselves!

The great thing about any roast is that, with heat penetrating from all sides, the ends are always more thoroughly cooked than the center. The same thing will happen for your roast. If you remove the meat from the oven when the center is 115°F to 120°F (46°C to 49°C), the center portion, even after it rests for 10 minutes, will be rare. Working outward toward the ends, the meat will be more well done – not well done, but more well done.

Our suggestion is to let the meat rest for five minutes after it comes out of the oven, lop off parent-sized portions from each end, and finish cooking them in a frying pan while the rare/medium-rare remainder of the roast finishes its rest. Another option, depending on how many people you are feeding and the size of your roast, would be to buy two filets mignon for your parents, and start them cooking in the oven ten minutes before you start the roast. When the roast is done, the filets should be well done.

With a larger cut of beef, such as a standing rib roast, the meat spends so much more time in the oven, it is possible to produce a roast that is rare in the center and at least medium-well done on the ends, if not actually well done. This is one instance where you do not want to cook the meat in a low-temperature oven, which results in a much more uniform level of "doneness" from end to center.

In the interests of full disclosure, the U.S. Department of Agriculture believes you should not eat or serve rare beef, but should bring the internal temperature (through roasting and resting) to at least 145°F (63°C), which they call medium rare. For well done, the internal USDA-approved temperature should be 170°F (77°C). We do not believe the agency has installed hidden cameras in every kitchen yet, so you may have one to two more years to turn out a rare beef tenderloin.