Method
Prep:45min  ›  Cook:15min  ›  Ready in:1hr 

1. Separate the thin leafy parts of the mustard greens from the thicker stems and set them aside in separate bowls. Place the onion, garlic, chillies, fennel, cumin and coriander in the bowl of a food processor and pulse until the mixture becomes a paste.
2. Heat the oil in a wok or large frying pan over medium-high heat; cook and stir the onion-garlic mixture until fragrant, about 1 minute. Stir in the beef and prawns; cook and stir until the beef is no longer pink and the prawns have become opaque, about 3 minutes.
3. Stir in the tomato puree and soy sauce; mix together until well combined. Stir in the noodles, tossing them with the sauce, beef and prawns until they have begun to soften, about 5 minutes. Add the mustard green stems, then cook and stir until the stems have begun to soften and become translucent, about 3 more minutes.
4. Stir the mustard green leafy parts into the dish and then the bean sprouts. Cook and stir everything together until the mustard green leaves and bean sprouts are softened but still bright in colour, about 3 more minutes. Season with salt to taste.

For the beef, substitute mutton or chicken cut into small pieces. For the prawn, substitute Chinese fishcakes or squid, cut into small pieces if desired.

Thai black soy sauce

This is different to the ordinary Chinese/Japanese soy sauces, which are not sweetened. Thai black soy sauce is made by fermenting soy sauce with sugar or molasses. It can be found in oriental supermarkets. If unavailable, use dark soy sauce with 2 teaspoons of sugar

Chinese mustard greens (gai choy)

Found in oriental stores. If this specific green is not available, substitute it for another oriental green, such as choy sum.