The filet mignon roast, also known as the beef tenderloin, is the tender muscle from the saddle area of the cow. This muscle is not used frequently, resulting in a very tender roast. While filet mignon roasts can be grilled or braised, they are often baked because they are small, lean roasts that overcook rapidly on the grill. The usual size for a filet mignon roast is 2 to 4 lbs., making the meat an ideal size for an elegant family dinner.
Preheat the oven to 450 degrees Fahrenheit.
Take the filet mignon roast out of the refrigerator and allow it to rest until it comes to room temperature, or 72 degrees Fahrenheit.
Trim the excess fat off the roast. If the roast still has the chain muscle, or long thin flap of meat, attached cut it off and reserve it for a different use.
Rub the filet roast with olive oil and garlic, if you are using it. Place the meat in the roasting pan.
Place the roasting pan in the oven and bake the filet mignon roast for 15 minutes. Roasting the filet for a few minutes at a high temperature will brown the outside, creating a savory crust.
Reduce the heat to 325 degrees Fahrenheit and continue to bake the filet roast for 20 more minutes.
Remove the roast from the oven and insert an instant-read meat thermometer into the center of the roast. The temperature should register 115 degrees Fahrenheit for a rare roast, 125 for medium-rare, 130 for medium, 140 for medium-well and 150 degrees for a well-done roast. If the roast is not yet at your desired temperature, return it to the oven and check the temperature every five minutes until it is cooked to your preferred temperature.
Allow the filet roast to rest for 10 minutes before you slice it into serving-sized pieces.