Season the steaks generously with the steak seasoning on both sides.
Heat olive oil in a large skillet over medium-high heat. Add the steaks and sear them for 4-5 minutes per side, or until browned and cooked to your desired level of doneness. Remove the steaks from the skillet and set aside.
In the same skillet, add the sliced onions and mushrooms. Cook for about 4-5 minutes, stirring occasionally, until they are softened and lightly browned. Add the minced garlic and cook for an additional 30 seconds until fragrant.
Sprinkle the flour over the mushrooms, onions and garlic. Stir to combine and cook for 1 minute. Gradually add the beef broth while whisking to prevent lumps. Stir in Worcestershire sauce. Bring the mixture to a simmer and cook for 3-5 minutes, or until the gravy thickens.
Return the steaks to the skillet, spoon some gravy over them, and let everything simmer together for an additional 5 minutes, ensuring the steaks are coated in the rich gravy.
Remove the steaks, mushrooms and onions from the skillet. Stir in butter for a smooth, glossy finish to the gravy. Serve the smothered steaks with mashed potatoes, rice, or your favorite side dish!