In a large pot, boil noodles according to package directions, strain, rinse, and set aside.
In a large pan or skillet, brown ground beef over medium-high heat until no longer pink and completely cooked. Drain grease and return to pan.
Add in onions, broccoli, celery, and carrots. Cook over medium-high heat until vegetables are tender.
In a small mixing bowl, combine soy sauce, brown sugar, sesame oil, Hoisin sauce, oyster sauce, garlic, and red pepper flakes. Stir well.
Pour sauce mixture into pan with ground beef and cooked vegetables and heat for 5-6 minutes or until sauce thickens and is heated through.
Add meat mixture to cooked noodles and stir/toss to combine.