Cook potatoes in water until tender. Mash with the milk and butter; cover and set aside.
Preheat oven to 375 degrees and grease a large casserole dish with vegetable spray.
In a skillet, saute the onion and mushrooms together with the elk meat, garlic and onion powder. Cook until no longer pink. Drain well and place on the bottom of the prepared casserole dish. Cover with mashed potatoes and spread out to sides (so it is sealed).
Bake for 30 minutes. Cover with the shredded cheese and bacon. Bake another 10 minutes or until cheese is melted. Serve with warm homemade bread and a salad.
For more delicious elk recipes, please visit www.MissHomemade.com.