4 pounds venison tenderloin
1 cup red wine
1/2 cup apple cider vinegar
1 medium onion, chopped
2 cloves garlic, crushed
2 bay leaves
2 sprigs fresh thyme
2 sprigs fresh rosemary
Combine the red wine, cider vinegar, onion, garlic, bay leaves, thyme and rosemary in a medium bowl, and mix well. Transfer to a large resealable bag, and put the venison tenderloin into the bag. Close tightly, pressing out as much air as you can. Place meat in the refrigerator to marinate, turning two or three times, for at least 12 hours.
Preheat the oven to 325 degrees F (165 degrees C). Remove meat from marinade, and place on a roasting rack in a roasting pan.
Roast in the oven for 2 to 2 1/2 hours or to your desired degree of doneness. For medium rare, the internal temperature of the roast should be at least 150 degrees F (65 degrees C) when taken with a meat thermometer. Let the roast stand for 15 to 20 minutes before carving.
While the tenderloin roasts, heat marinade in a saucepan over medium heat. Simmer until the liquid is reduced by 1/3. Serve with venison.