Boil 200 grams of noodles as per the package instructions. Drain and set aside.
In a small bowl, mix 60 ml of soy sauce, 60 ml of water, 30 grams of brown sugar, 15 ml of rice vinegar, 1 teaspoon of minced garlic, and 1 teaspoon of minced ginger. This will be your teriyaki sauce.
Heat 30 ml of oil in a large pan or wok over medium heat. Add 1 chopped onion, 1 chopped bell pepper, 1 chopped carrot, and 100 grams of chopped broccoli. Stir fry the vegetables for 5-7 minutes until they are tender-crisp.
Add the cooked noodles and the teriyaki sauce to the pan with the vegetables. Stir fry for another 2-3 minutes, ensuring that the noodles and vegetables are well coated with the sauce.
Garnish with 1 tablespoon of chopped spring onions and 1 tablespoon of toasted sesame seeds before serving.