Preheat your oven to 350ºF and spray a baking sheet with cooking spray.
In a large bowl combine the ground elk, mushrooms, onions, apple, tomato sauce, breadcrumbs, salt, and pepper.
Shape meat mixture into a loaf on the baking sheet.
In a small bowl combine the brown sugar, mustard, ketchup, and apple cider vinegar. Brush over the meatloaf, glazing entirely.
Bake until a thermometer inserted reaches 165ºF, about 65 minutes. Remove from oven and serve.
You can also bake this in a loaf pan. Cooking times may differ.
This recipe works well with other ground meats, like turkey or beef.
Serve this Elk Meatloaf with Fried Apple Fritters for dessert.