Heat the cooking oil in a wide pan over medium-low heat. Add the garlic and cook while stirring until it turns light golden brown. Remove the garlic using a fine-mesh strainer and set it aside. Reserve the garlic oil.
15 cloves garlic, 1/4 cup cooking oil
Heat 1 tablespoon of garlic oil in the same pan over medium-high heat. Add half of the beef and sear for 1 to 2 minutes, stirring only as needed, until the outside browns. Transfer it to a plate. Add another tablespoon of garlic oil and repeat with the remaining beef.
1 1/2 lbs beef sirloin
Return all the beef to the pan. Pour in the soy sauce and oyster sauce, then add the coarsely ground black pepper and half of the toasted garlic. Toss for 30 seconds to 1 minute, or until the sauce lightly coats the beef and no loose liquid remains in the pan. Transfer the beef to a clean plate.
2 tablespoons soy sauce, 2 tablespoons oyster sauce, 1 teaspoon coarsely ground black pepper
Add 1 tablespoon of the reserved garlic oil to the pan. Add the mushrooms and cook over medium-high heat for 5 to 7 minutes, stirring occasionally, until the mushrooms brown and most of the liquid they release has evaporated. Remove the mushrooms from the pan and set them aside.
14 oz button mushrooms
Melt the butter in the same pan over medium heat. Add the flour and stir continuously for 1 1/2 to 2 minutes, or until the mixture becomes smooth and lightly golden. Gradually pour in the beef broth while whisking to prevent lumps. Add the onion powder, garlic powder, and ground black pepper, then return the mushrooms to the pan. Simmer for 3 to 5 minutes, or until the gravy is smooth and thick enough to coat the back of a spoon. Taste and add salt only if needed.
3 tablespoons butter, 3 tablespoons all-purpose flour, 2 cups low-sodium beef broth, 1/2 teaspoon onion powder, 1/4 teaspoon garlic powder, 1/4 teaspoon ground black pepper, Salt
Return the beef and any juices from the plate to the pan. Toss until the beef is evenly coated with the mushroom gravy, then cook for 30 seconds to 1 minute, just until heated through. Add a small amount of broth if the gravy becomes too thick. Transfer to a serving plate and top with the remaining toasted garlic. Serve warm. Share and enjoy!