Take the noodles out of the package. Soak them in warm water for a few minutes. Afterwards, use your fingers to gently loosen up the noodles. Then give the noodles a quick rinse under running water. Set aside so they can drip off excess water.
Dice onion, carrot and Shiitake mushroom into thin slices. Cut a few layers off the green cabbage and dice them into small-sized pieces. Then cut your spring onion stalks into bite-sized rectangular pieces. If you're using shrimp, clean and de-vein them.
Make Yakisoba Sauce: Mix Worcestershire Sauce (4 Tablespoons), Oyster Sauce (2 Tablespoons), Water (1 Tablespoon), Ketchup (1 Tablespoon) and Sugar (½ Tablespoon).