01 - Heat 1 tablespoon of olive oil and 1 tablespoon of butter in a large skillet over medium-high heat.
02 - Add beef pieces in a single layer, season with salt and pepper, and sear for 2–3 minutes per side until browned. Work in batches if needed. Set browned beef aside on a plate.
03 - Lower heat to medium. Add the remaining olive oil and butter to the skillet. Sauté onions and mushrooms (if using) for 2–3 minutes until softened. Stir in garlic and cook for 1 minute until fragrant.
04 - Sprinkle flour over the vegetable mixture, stirring well for about 1 minute to cook off the raw flour taste.
05 - Slowly pour in beef broth while stirring and scraping up any browned bits from the bottom of the pan. Stir in Worcestershire sauce and dried thyme.
06 - Bring to a gentle simmer. Return the steak tips and any accumulated juices to the skillet. Cook uncovered, stirring occasionally, for 8–10 minutes until the beef is tender and the gravy has thickened.
07 - Taste the gravy and adjust salt and pepper as needed.
08 - Sprinkle with fresh parsley and serve hot over rice, mashed potatoes, or egg noodles.