Cut the steaks about 1.5" thick. I'd use the sous vide circulator at about 125F, with some olive oil, red wine, garlic, thyme, diced onions, diced celery, diced carrots, and parsley in the bag, for about 2 hours. Make sure you strip the silver skin before you cut them. Once you take them out of the bath, sear on each side for a minute in a hot skillet and rest for 10 before eating. While it's resting, you can reduce the liquids from the bag and take out the thyme and parsley. Slice the steaks on the plate and pour the liquid over the meat (if you need to thicken for gravy, either make a roux or you can thicken with a little cornstarch and water paste). If you don't have a circulator, then marinate the steaks in the above ingredients for 6 hours and then grill them to an internal temp of 125F - use a thermometer. Not too hot, unless you like a tough crust on the outside. Nothing is so unholy as overcooking game, especially tenderloins.
