Cook your choice of noodles according to package instructions for about 4-6 minutes until al dente, then drain and rinse under cold water.

In a large skillet, heat vegetable oil over medium-high heat. Add ground beef and cook for 5-7 minutes, breaking it apart until browned. Drain excess fat.

Lower heat and add chopped onion to the skillet. Sauté for 2-3 minutes until translucent, then add garlic and ginger, cooking for another minute.

Add sliced carrots and bell peppers; stir-fry for 2-3 minutes until tender-crisp.

In a bowl, combine soy sauce, oyster sauce, hoisin sauce, sesame oil, brown sugar, and red pepper flakes. Whisk until mixed.

Add cooked noodles into the skillet with beef and veggies. Pour sauce over and toss to coat evenly, stir-frying for another 2-3 minutes.

Remove from heat and serve garnished with sesame seeds and sliced green onions.