Boil the noodles until soft, 6-8 minutes or until cooked through. Cool under a running cold tap, drain and set aside.
In a small bowl, mix together the chicken stock granules, soy sauce, black soy sauce and sesame oil to make the sauce. Set aside.
Heat a large frying pan with 1 tablespoon oil over high heat. Stir-fry the garlic until fragrant, 2-3 minutes. Add and stir-fry the spring onions, onion and salt until soft, 3-4 minutes.
Add the bean sprouts and sauce. Adjust the seasoning accordingly with salt. Stir in the peppers and noodles and mix well. Continue to cook until the sauce has almost dried out. Serve and garnish with roasted sesame seeds.
Black soy sauce can be found in Chinese/Oriental speciality stores.