Preheat your oven to 175°C (350°F) and grease a 23x33 cm (9x13-inch) baking dish with non-stick spray.
In a medium bowl, whisk together the condensed cream of mushroom soup and whole milk until well combined. Stir in the freshly chopped parsley. Set the gravy mixture aside.
In a separate large bowl, combine the ground beef, crushed saltine crackers, whole milk, Italian seasoning, garlic powder, onion powder, and cayenne pepper. Season the mixture generously with salt and pepper.
Using your hands or two forks, gently mix the ingredients until just combined. Shape the mixture into evenly-sized patties.
Place the all-purpose flour (approximately 1 cup, or more as needed) in a shallow dish and dredge each patty in the flour, coating both sides.
Heat a large skillet over medium-high heat. Once the skillet is hot, sear the patties on both sides until golden brown. You may need to work in batches, ensuring that the insides remain undercooked.
Transfer the browned patties to the greased baking dish. Pour the prepared gravy evenly over the patties, covering them completely. Cover the baking dish with aluminum foil.
Place the baking dish in the preheated oven and bake for 30-40 minutes or until the patties are cooked through.
Serve the Amish Country Poor Man's Hamburger Steaks hot with the rich mushroom gravy, accompanied by your choice of sides.