Place Ground Beef and diced onion in a large sauté pan. Brown meat and onion. Once completely browned, drain all fat. Season with salt and pepper. Sprinkle meat mixture with numerous dashes of Worcestershire Sauce and stir (I typically add Worcestershire sauce until I can smell it’s aroma on the meat). Sprinkle gravy master, enough so that once mixed the meat has a dark brown hue. Set entire pan aside.
In a second sauté pan melt butter and add oil. Add mushrooms and garlic to oil/butter mixture and sauté until tender and liquid greatly reduces. Finish off mushrooms by adding Whiskey and cooking until it evaporates. Season with Salt and Pepper. Set sauté pan aside.
In a small stock pot prepare onion gravy. Follow directions on the package and add beef stock in place of the water. Add an additional cup of Beef Stock. Once Gravy is boiling stir in Bisto Gravy mix to thicken. Start with 2 tablespoons and add additional Bisto if you would like the gravy to be slightly thicker. Stir the Gravy into the Ground Beef Mixture.
In a roasting pan layer the Ground Beef Mixture, Mushrooms, Steamed Mixed Vegetables, and Mashed Potatoes. Place roasting pan into the oven and broil on low until golden brown and bubbly. This dish can also be put together in individual servings.
Bisto will create lumps if granules are poured directly into hot gravy mixture. Make a slurry with the Bisto and cool water in a separate bowl, then whisk into gravy to thicken.