Add beef to a gallon zippered bag. Pour in half of the sauce and smoosh around to evenly coat. Secure zipper and place in refrigerator to marinate for at least 30 minutes (up to 24hrs). Cover remaining sauce and place in refrigerator until ready to prepare rest of meal.
Prepare yakisoba noodles as directed on packaging. (Usually rinsing in a colander with warm water).
In a large saute pan or wok over high heat, add beef (with all of the marinating liquid). Stir fry for about 4 minutes (until no longer pink).
Add carrots, bell peppers, green onions, and peas. Stir fry another 4 minutes. Then add prepared noodles along with remaining sauce. Stir fry and toss to evenly coat for 4 minutes more. Remove from heat and serve right away.
Keyword beef, beef lo mein, carrots, lo mein, noodles, oyster sauce, red bell peppers, snap peas, soy sauce, yakisoba noodles