Traditional recipes for deer call for marinating the roast in a strongly-flavored liquid for up to three days. That's largely intended to tame the gamy flavor of mature wild venison, but it isn't necessary with the milder, tenderer roasts of farmed deer that you find at the butcher's shop. The same marinate flavors still work well with the tender roasts, but you don't have to marinate them as long.
Marinating the Venison
Combine your marinade ingredients in a large pot. Traditional marinades for venison include a combination of ingredients such as red wine and red wine vinegar, peppercorns, onions, garlic, bay leaves and thyme. You typically also include juniper berries for their distinctively "woodsy" flavor.
Bring the marinade to a gentle simmer for 10 to 15 minutes, and then let it cool to room temperature. This helps infuse the marinade with the flavors of its aromatic ingredients.
Remove any lumps of fat from the surface of your roast, but if it has a rind of fat on one side leave that in place. If your roast contains a bone, wipe the ends of the bone with a paper towel to remove any debris from the butcher's saw. Dry the surface of the roast with a clean paper towel.
Place the roast in a container of glass, stainless steel or food-grade plastic that's just large enough to hold it comfortably. Pour the cooled marinade over the roast, and cover the container with a lid or plastic film wrap.
Refrigerate the roast in the marinade for at least 30 minutes, or as long as overnight. The shorter time flavors the meat gently, and leaves the focus on the venison's natural flavor. Longer marinating gives the venison a more classical, wine-based flavor.
Roasting the Venison
Remove the venison roast from its marinade. Pat it dry with clean paper towels.
Season the surface of the roast with salt and pepper, and sear it on all sides in a hot skillet until it's well browned. If your roast has a cap of fat, slash shallow cuts into it with the tip of a sharp knife. This will help the fat render out, keeping the roast moist and protecting it from the dry oven.
Transfer the venison to a roasting pan with a rack. If your pan has no rack, coarsely chop a mixture of carrots, celery and onions and place them in the bottom of the pan. Rest the roast on top of the vegetables, which will keep it above the drippings.
Roast the venison slowly at 325 degrees Fahrenheit until its internal temperature reaches the USDA's recommended food safe level of 160 degrees F, approximately 20 minutes per pound for boneless roasts or 30 minutes for bone-in roasts. You can roast tenderloins at 425 degrees F for approximately 45 minutes.
Rest the roast for at least 10 minutes and preferably 15 to 20 minutes before you carve it. That gives time for the roast's juices to be reabsorbed by the muscle tissues, keeping the meat moister and more flavorful.
Braising the Venison
Remove your venison roast from the marinade and carefully pat it dry with paper towels. Sear it in a hot skillet, until its entire surface is well browned. This step is optional, but makes the flavor richer.
Place the roast in a deep stainless-steel or tempered glass roasting pan, and add enough of the marinade to submerge at least the bottom one-third of the roast.
Cover the roaster and place it in a preheated oven at 300 to 325 degrees F. Baste the top periodically with the marinade, or turn the roast after the first two hours of cooking.
Slow-cook the roast for at least three to four hours, until its internal temperature is above 160 degrees F and it's fork-tender. The toughest leg and shoulder cuts might require four to six hours' cooking to become fork-tender, at an internal temperature of 180 degrees F or higher.
Remove the roast to a serving dish, cover it, and keep it warm. Strain the flavorings from your marinade, and reduce or thicken it to make a sauce for the meat.