Double the marinade recipe and combine according to the instructions—reserve half of the marinade to make a sauce. Store in the refrigerator until needed.
Place venison tenderloins into a large glass dish or zip-top bag. Pour the remaining half of the marinade over the meat, coating well. Seal the bag or cover the dish with plastic wrap, and place into the refrigerator for 1- 1 1/2 hours.
Preheat your smoker or pellet grill to 225 degrees F. If using a smoker, add chunks or chips 5 minutes before the meat goes on. Follow the manufacturer's recommendations for best results.
While the smoker is heating, remove meat from the refrigerator, and let it stand at room temperature for at least 20 minutes.
Place venison tenderloins directly onto the grill grates. Close the lid, and cook for 1- 1 1/2 hours or until they reach an internal temp of 125 degrees F
For charcoal grill: Move tenderloins over to the hotter part of the grill to reverse sear them. Use tongs to turn them for even searing. For pellet grill: Remove tenderloins and crank the heat up to 500 degrees F. Once heated, place the tenderloin back on the grill and sear them. Once the venison is cooked, remove them from your grill or smoker, and place them onto a cutting board. Loosely tent with aluminum foil, and rest the meat for 10 minutes.
For sauce: Bring the refrigerated, reserved marinade to a simmer in a small saucepan for 5-6 minutes. Follow the recipe instructions to thicken the sauce as needed.
Slice tenderloin into 3/4" medallions, and place them onto a platter. Drizzle with warm sauce and garnish with fresh herbs and optional toppings. Serve immediately.
Store leftover smoked venison tenderloin in an airtight container in the refrigerator for 3-4 days. Reheat in a skillet over medium heat or in a 300-degree oven until warmed through.