In a medium bowl, add the bread and milk to make a panade. Gently push the bread into the milk and set aside for 5 minutes. In a larger mixing bowl, add the beef, 3/4 teaspoon salt, 3/4 teaspoon pepper, and the rest of the ingredients. Add the panade mixture (including any leftover milk) to the beef mixture and gently mix until combined.
Divide the mixture into 6 sections and form each patty into a football/egg/oval shape where it’s thicker in the middle. Place them on a lightly sprayed dish. Cover with plastic wrap and chill for 30 minutes.
Preheat the oven to 350F, rack in the middle. Lightly spray a 9×13” baking pan. Set aside. In a medium non-stick skillet over medium heat or if using a stainless steel pan add 1 tablespoon oil. Remove the Salisbury Steak patties from the fridge and cook up 2-3 Salisbury Steak patties at a time (do not crowd the pan). Cook for 5-7 minutes per side or until each side is browned. *Be very gentle in flipping these. You can skip searing these in the pan if you want and put them directly into the 9×13” pan if you wish. Place each seared patty into the baking dish in a single layer.
Mushroom & Shallot Gravy
To the pan used to make the Salisbury Steak patties add the 2 tablespoon of butter and allow to melt. Add in the mushrooms and shallots and gently stir. Cook for 5-6 minutes or until the shallots start to soften and the mushrooms just start to release their water. You’re not cooking the mushrooms all the way down. Spoon out the mushrooms and shallots and place overtop the Salisbury steak patties.
Put the pan back onto the stovetop, medium heat and add 1/4 cup of beef stock. Using a wooden spoon, gently scrape up any browned bits. Add the rest of the stock, gravy master, remaining 3/4 teaspoon of salt and 3/4 teaspoon of black pepper and bring to a boil. In a separate bowl, whisk together the cornstarch and heavy cream to make a slurry. While whisking the stock, pour in the slurry in slowly. Whisk and bring back to a boil. The mixture should thicken up in 5-6 minutes. It should coat the back of a spoon in a thick glaze.
Pour the mixture over top of Salisbury Steak patties and sautéed vegetables.
Bake
Place the 9×13” pan into the oven, uncovered and bake for 35-45 minutes or until the Salisbury Steak patties read 165F.
Remove from the oven, allow to rest for 10 minutes and serve.