In a large mixing bowl, break up the venison a little bit with your hands to make it easier to mix. Now add the minced onion and garlic, breadcrumbs, egg, onion powder, garlic powder, parsley, and salt and pepper. Mix well.
Divide the mixture into 6 or 8 portions. Form the portions into oval patties that are about 1/2-inch thick.
In a large skillet melt a tablespoon of ghee or olive oil over medium heat.
Add the Venison Salisbury Steaks in 2 batches and fry them over medium heat for 2 to 3 minutes on each side to sear.
After both sides of the patties are brown, remove them from the pan to a platter and cover to keep warm. Set aside.
Repeat until all the patties are browned.
Using the same frying pan, add another tablespoon of ghee or olive oil and let it melt.
Add the sliced onions to the pan. Cook these over medium high heat for about 5 minutes until translucent and beginning to caramelize.
If you are using fresh mushrooms add those in now. And continue to cook and stir for another 3 minutes.
Using a whisk, add the flour, garlic powder, and thyme and combine with the onions.
Let that cook and brown for 1 minute, whisking continuously.
Pour in the beef stock or game stock all at once. Continue to whisk that all together. Make sure to scrape the bits off the bottom of the skillet.
If you are using canned mushrooms, add those and the liquid now and whisk that in.
Continue to whisk the gravy until it comes to a boil then lower the heat just a tad so the gravy simmers.
Continue to simmer and whisk until the gravy thickens, then add 1 tablespoon butter and stir until it's melted.
Once the gravy has thickened up, add the Venison Salisbury Steaks back to the pan with the gravy mixture. Ladle some of that gravy over the steaks, and cook for 5 minutes.
About halfway through you can switch some of the patties around if they aren’t all covered with gravy.
Remove from heat and serve.