01 - Heat 1 tablespoon of olive oil and 1 tablespoon of butter in a large skillet over medium-high heat. Add beef pieces in a single layer, season generously with salt and pepper, and sear for 2 to 3 minutes per side until well browned. Work in batches to avoid crowding the pan. Transfer browned beef to a plate and set aside.
02 - Reduce heat to medium. Add the remaining olive oil and butter to the skillet. Sauté diced onions and mushrooms for 2 to 3 minutes until softened. Stir in minced garlic and cook for 1 minute until fragrant.
03 - Sprinkle flour over the vegetable mixture and stir continuously for about 1 minute to cook off the raw flour taste and form a smooth roux.
04 - Slowly pour in beef broth while stirring constantly and scraping up any browned bits from the bottom of the pan. Stir in Worcestershire sauce and dried thyme until well combined.
05 - Bring the mixture to a gentle simmer. Return the seared beef and any accumulated juices to the skillet. Cook uncovered, stirring occasionally, for 8 to 10 minutes until the beef is tender and the gravy has thickened to your preferred consistency.
06 - Taste the gravy and adjust salt and pepper as needed. Sprinkle with fresh chopped parsley and serve hot over rice, mashed potatoes, or egg noodles.