Remove any silver skin from venison backstrap. Slice crossways into 3/4' to 1" slabs.
Lightly season them with salt, pepper, cajun or seasoning of your choice. Wrap a slice of bacon tightly around the slab and pin with a toothpick. Slice onion and place on top of each mignon. In a shallow dish, pour a little of the marinade to cover the bottom, then place each mignon in the dish and pour additional marinade over the meat. Refrigerate the remaining marinade.
Cover the dish and refrigerate for 12 hours then flip the mignons.
Cover and refrigerate for an additional 12 hours.
Remove from refrigerator, and remove onions for later sauteing.
Grill mignons and brush on marinade as it cooks until pink barely shows in the middle of the meat.
Saute' the onions and garlic and garnish the mignons.