Step 1

Heat 1/2 teaspoon of the oil in a large saucepan over medium-high heat. Cook the beef for 2 mins each side or until browned. Transfer to a heatproof bowl.

Step 2

Heat 1/2 teaspoon of the remaining oil in the pan. Add the leek and cook, stirring, for 2 mins or until leek softens. Add the chilli powder, if using, garlic and ginger and cook, stirring, for 1 min or until aromatic. Return the beef to the pan with the shiitake mushroom and cook for 1 min. Add the stock and 2 cups (500ml) water. Bring to the boil. Reduce heat to low.

Step 3

Cook, partially covered, for 2 hours or until beef is very tender. Use tongs to transfer the beef to a heatproof bowl. Use 2 forks to coarsely shred the beef. Return to the pan with the soy sauce and remaining oil.

Step 4

Add the carrot, bean sprouts, oyster mushroom and half the enoki mushrooms to the beef mixture. Stir to combine. Divide the soup evenly among serving bowls. Top with spring onion and remaining enoki mushrooms.