The prime cut of venison is the tenderloin— often called the "backstrap." It is truly worth of the cleaning effort required. Once you have it properly cleaned, it requires no massive marinading to render it tender and delicious. The only way to mess it up is to overcook it.
Beginning with about a 3 pound tenderloin section, trimmed and dry, mix:
4 Tbs. lard, beef suet or peanut oil
2 cloves garlic, crushed
2 tsp. new, fresh onion powder
1 tsp. salt
1/2 tsp. powdered thyme
1/2 tsp. powdered bay leaf
1/2 tsp. cayenne pepper
1/2 tsp. black pepper
Put all ingredients into sauce pan heat to about 150 degrees - just enough to wake up the sleeping flavors. Allow to cool and rub the meat thoroughly with the mixture.
Fire up the grill for roasting - 350 degrees. White oak and hickory for smoke. Sufficient fuel for a couple of hours of cooking at 350.
Baste the loin again and put it on the grill. Place a drip pan under the loin to catch the drippings. Baste about every 15 minutes until all the baste is used.
In about 1 1/2 hours, check the internal temperature with your handy thermometer. Remove from the grill when the center reaches 145 degrees. Let it rest while you de-glaze the drip pan with water. Reduce the liquid to 1/2 and add 1/4 cup sliced mushrooms. Simmer and season.
Slice the loin thinly across the grain. It should be so tender and juicy that you may want to save the gravy for later.