Steps

• Start by cutting the beef sirloin into bite-sized chunks. Season generously with salt and pepper to enhance flavor. Set aside to let the seasoning penetrate while you gather other ingredients.
• Heat olive oil in a large skillet over medium-high heat. Add the beef chunks in a single layer, ensuring they sear well. Browning the beef is crucial, as it locks in juices and adds a deep, savory flavor to the dish. Cook until browned on all sides, about 4–5 minutes, then remove and set aside.
• In the same skillet, add butter and allow it to melt. Toss in the diced onions and minced garlic. Sauté until onions are translucent and garlic is fragrant, about 2 minutes. Add mushrooms and continue to cook until they soften.
• Stir in the flour to the vegetable mixture until it coats them evenly, cooking for about 1 minute. Slowly pour in the beef broth while whisking continuously to prevent lumps. Season with additional salt and pepper as needed.
• Return the browned beef to the skillet, combining it with the mushroom gravy. Lower the heat to a gentle simmer. Cover and cook for 20–25 minutes, or until the beef is tender and flavors meld beautifully together.