Heat up a wok with 2 tablespoons of sesame oil. Transfer the rice noodles into a wok, add 2 tablespoons of soy sauce and eggs, and stir the noodles vigorously to spread the fish sauce and eggs evenly. Set aside.
Add 2 tablespoons of sesame oil to the wok. Add garlic and beef, and cook for 3-5 minutes or until the beef turn brown.
Add the broth, vegetable, fish sauce, soy sauce, and oyster sauce. Adjust the taste. Bring the sauce to a boil and then thickens it with the cornstarch water. Turn off the heat as soon as the sauce is thick and gooey.
Place a portion of flat rice noodles in a bowl, then pour the gravy over the noodles.