Place the round steak in a large Ziploc bag or shallow dish. Pour the marinade ingredients over the steak, ensuring it's evenly coated. Seal the bag or cover the dish, and place it in the refrigerator. Let it marinate for 2 to 4 hours or overnight.
Preheat the oven to 325 degrees F (165 degrees C) and in a bowl combine the onion powder, garlic powder, Italian seasoning, salt, and black pepper. Season both sides of the steak generously with the seasoning, leaving a little left for the next step.
In a shallow dish, mix the flour with the remaining seasoning mix. Coat the steak evenly with the seasoned flour, shaking off excess.
Heat 2 tablespoons of oil in a large oven-safe skillet over medium-high heat. Add the steak to the hot skillet and cook it for 4-5 minutes on each side until it is well browned. Remove the steak and set it aside on a plate.
In the same skillet, reduce the heat to medium and then add a tablespoon of oil, and sliced onions. Cook them for 5-7 minutes, stirring occasionally, until the onions are soft and lightly caramelized add in the minced garlic and cook until fragrant.
In a mixing bowl, combine cream of mushroom soup, beef broth, Worcestershire sauce, and brown gravy mix. Whisk them until well combined.
Carefully return the steak to the skillet and then pour the sauce mixture over the steak. Cover the skillet tightly with aluminum foil and then transfer it to the preheated oven and bake it for 2-3 hours, or until the steak is very tender when pierced with a fork.
Remove the hot pan from the oven and let it rest, covered, for 10 minutes before slicing against the grain.