My family's Christmas traditions have evolved over the years, but the centerpiece of our Christmas Eve dinner menu has always been the same: an entire roasted beef tenderloin. Not only is it tender and flavorful, but cooking it whole, rather than in separate filet steaks, is quick and easy. It's also an ideal dish for picky eaters because different sections of the tapered cut cook at different rates. At our holiday table, the red-to-pink continuum goes something like this: my grandfather and my aunt get slices of bloodred, rare meat from the thicker, butt end of the roast; the medium-rare slices from the center section are portioned out to me and my cousins; and my mom claims the slices from the narrower, tail end, which cooks to a perfect medium. For years, my grandmother and my aunt took on tenderloin duty, rubbing the beef with salt and pepper and roasting it in a low oven. They recently passed the baton to me, and in the years since, I've taken a few liberties, adding an herb-and-peppercorn crust to the tenderloin and cranking up the oven's temperature in order to achieve a crisp exterior. My adaptations have been well received, for the most part. Last year, my 92-year-old grandfather grumbled, "Are you putting on that damn crust again?" Still, I couldn't help noticing that he took a second helping.