Combine the chicken, soy sauce, sesame oil, white pepper and corn flour and leave aside to marinate for 15 minutes.
In a small pot, heat a little oil till hot and sear the chicken until browned all over. The chicken doesn't have to be cooked thoroughly. Remove from heat and set aside.
In the same pot, add in a little more oil and stir fry the ikan bilis / ice fish and the onion until the ikan bilis is slightly golden and the onion is translucent. Use the mushroom water and fill up to half a bowl of water, add it in with the ikan bilis and onion and bring to boil.
Once the water has boiled, add in the chicken, shiitake mushrooms and carrot. Cover and simmer for 10 minutes until the soup is flavourful.
Add in the noodles and egg and cook until the noodles have softened. If you like your egg to have oozy yolk, add in the egg slightly later. Season with salt to taste.