Directions:
Put the stock into a saucepan and bring to the boil. Once boiling, turn down to a simmer and add the onion, celery, half the sliced mushrooms, garlic, ginger, coriander, oyster sauce, soy sauce, and black pepper.
Simmer for 10 minutes.
While the soup is simmering, place the rice noodles in a separate bowl or pot and pour in enough boiling water to cover them. Separate the noodles with a fork and leave them to sit in the hot water for 10 minutes. Drain.
Thinly slice the beef. Turn the soup mixture up to a fast simmer, and then dunk the slices of beef into it in single layered batches using a slotted spoon or similar. Do not cook the meat for more than 30 seconds; it should be only lightly cooked.
Put the beef aside in a warm place.
Turn the soup back down to a gentle simmer and skim off any scum.
Prepare the bowls:
Divide the cooked noodles, shredded lettuce, bean sprouts, and the rest of the sliced mushrooms into large soup bowls, and then place beef strips on top. Pour the hot soup over the vegetables and serve immediately. The soup will lightly cook the vegetables and will finish off the beef perfectly.
Alternatively, you can put all the ingredients on the table and have people build their own soup. If you want other vegetables, you can try adding snow peas, shredded carrot or other Asian veggies.
