Season venison chops (to taste) using your favorite seasoning salt. Place flour, cornstarch, and touch of salt and pepper into large plastic bag (do not over season). Put venison chops individually into the bag, shake to coat well. Once all chops are coated, remove from bag to a plate. Press coating into chops then let sit at room temperature for at least 10 minutes to help the flour stick to the venison. Meanwhile, preheat a large cast iron skillet to medium-high heat. Also, preheat oven to 350°. Melt butter in skillet. Add onion and sauté until almost transparent. Add package of sliced mushrooms (season with salt and pepper). Allow onions and mushrooms to sweat and caramelize. Just before onions and mushrooms are finished add the minced garlic stirring to incorporate, about 2 minutes. Do not let the garlic burn, as it will taste bitter. Once onions, mushrooms, and garlic are done remove to a plate. With the skillet still at medium-high heat, melt 2 tablespoons of butter. Place venison into melted butter and brown on each side. This will sear in the juices, not cook the venison completely through. Once browned, drain oil then return onions, mushrooms, and garlic mixture to the pan. Also add in entire can of beef or mushroom gravy. Make sure chops are mostly covered. Place the uncovered skillet in the oven for 10 minutes to finish the dish. Remove from oven, garnish with freshly chopped green onions and serve. Great with mashed potatoes or a bed of butter and garlic pasta.