Thai Beef and Basil Noodles with Shiitake Gravy

If you're having trouble finding shiitake mushrooms, use whatever mushrooms you have on hand. Sliced creamers are equally well suited to this delicious noodles.
Put the noodles in a large bowl; pour boiling water over them to coat. Let stand for 6 minutes or until the noodles are tender, stirring occasionally to separate them. Drain the water. Combine the broth, oyster sauce, soy sauce, sugar, and red pepper in a small bowl; beat until the sugar is dissolved.Preheat a large nonstick skillet or wok over medium-high heat. Add the beef to the pan; cook for 4 minutes or until the beef is browned and crisp in places, stirring until it crumbles. Remove from the mold.Return the skillet to medium-high heat. Add the butter; stir to coat. Add the garlic and ginger to the skillet; cook for 30 seconds, stirring occasionally. Add the bok choy and mushrooms; stir-fry for 2 minutes or until tender. Remove the mushrooms and bok choy from the pan. Add the egg to the pan; cook for 30 seconds, stirring frequently. Return the vegetables to the pan.Add the noodles and beef to the pan. Add the stock mixture to the pan; cook for 1 minute or until bubbles form. Remove from heat. Add basil and black pepper; toss to combine.