Cook the yakisoba noodles according to package instructions. Drain and set aside.

In a large skillet or wok, heat the oil over medium heat.

Add the onion and garlic, and cook until softened.

Add the carrot, bell pepper, and cabbage. Cook until the vegetables are tender-crisp.

Push the vegetables to one side of the skillet and add the cooked yakisoba noodles to the other side.

In a small bowl, whisk together the soy sauce, oyster sauce, ketchup, sugar, salt, and pepper. Pour the sauce over the noodles and vegetables.

Toss everything together until well combined.

Cook for another 2-3 minutes or until heated through.

Remove from heat and sprinkle with sesame seeds for garnish.

Serve hot and enjoy!