Marinade shrimp and chicken with soy sauce and pepper. Set aside.
Heat 3 tablespoons vegetable oil in a wok or large fry pan. Fry yee meen until slightly crisp, about 4 to 5 minutes. Remove and divide noodles onto 4 plates. Set aside.
In the same pan, heat remaining 2 tablespoons of oil. Sauté garlic for about 1 minute. Add marinated shrimp and chicken and fry for 2 to 3 minutes.
Add chicken stock and bring to a boil. Season with salt.
Add choy sum and corn starch mixture. When stock comes back to a boil and thickens, stir in egg and immediately turn off heat.
Pour sauce over noodles. Let it sit for 1 to 2 minutes.
Serve with pickled green chilies or cut red chilies in soy sauce.
Notes
** May be substituted with 6 oz (170g) dried thin rice noodles and 6 oz (170g) dried flat cut rice noodles. Soak thin noodles in water for 15 minutes. Drain. Bring a large pot of water to boil. Turn off heat and soak flat cut noodles in boiling water for 10 minutes. Drain. Mix in a teaspoon of vegetable oil to prevent sticking. Heat 2 tablespoons vegetable oil in a wok or large pan. Add drained thin rice noodles. Fry noodles with 1 teaspoon soy sauce until slightly crispy, about 4 to 5 minutes. Remove and set aside. Repeat with flat cut rice noodles. **You can also use 1½ lbs (675g) fresh flat cut rice noodles. Place rice noodles in a large microwavable dish and microwave on high for 3 minutes to loosen up noodles. Remove and separate noodles into strands. Heat a large pan with 2 tablespoons oil. Fry noodles with 1 tablespoon soy sauce until slightly crisp, about 4 to 5 minutes. Here are the 3 out of the 4 different kinds of noodles used in this recipe - pancit canton, maifun (dried thin rice noodles), and hor fun (fresh flat cut rice noodles).