- One 6- to 8-pound beef tenderloin, trimmed of fat
- 1 cup port
- 1 cup soy sauce
- ½ cup olive oil
- 1½ teaspoons freshly ground black pepper
- 1 teaspoon dried thyme
- ½ teaspoon Tabasco sauce
- 4 cloves garlic, crushed
- 2 cups sour cream
- ¼ cup prepared white horseradish
- Cut the tenderloin in half and place each half in a zippered-top plastic bag.
- To make the marinade, combine all the ingredients in a medium-size bowl, then divide it evenly between the 2 bags. Seal the bags, turn them over a few times to coat the meat all over, and refrigerate for at least a few hours or overnight, turning the bags several times.
- Preheat the oven to 425°F.
- Remove the tenderloins from the bags, reserving the marinade, and place on a rack in a large roasting pan. Roast until medium rare, 140°F on an instant-read meat thermometer, or to your desired degree of doneness, 30 to 40 minutes. Keep checking the temperature; you don’t want to overcook this. (Remember, the thinner piece of the tenderloin wil cook faster.) Remove from the oven and let rest for 10 to 15 minutes to let the juices settle.
- Meanwhile, make the horseradish sauce by combining the ingredients in a glass serving bowl.
- Slice the tenderloins ½ inch thick and serve the sauce on the side.