Step 1

Combine wasabi, teriyaki marinade, fish sauce, garlic and sugar in a large bowl. Add beef. Coat well in the marinade.

Step 2

Meanwhile, prepare the noodles following the packet directions.

Step 3

Heat half the oil in a large wok over high heat until smoking. Swirl to coat the base. Cook half the beef, shaking the wok often, for 1-2 minutes, until the meat is seared but still rare in the centre or until cooked to your liking. Transfer to a dish. Keep warm. Repeat with remaining oil and beef. Remove beef. Add remaining marinade to the pan and cook for 1-2 minutes or until reduced and sticky. Return the beef. Toss to coat.

Step 4

Arrange noodles, tomato and watercress on serving plates. Top with beef and onion.