1. Soak the rice noodles in boiling water for 5-6 minutes until softened.
2. Meanwhile, heat 1 tablespoon of the oil in a large wok or frying pan over high heat. Add the mushrooms and stir fry for about 3 minutes. Remove from the pan and set aside in a large bowl. Heat 1 tablespoon oil in the pan, add the corn and snow peas and 2 tablespoons water and stir fry for 3 minutes. Add to the mushrooms. Add the remaining tablespoon of oil to the pan and add the garlic and beef and stir fry for 2 minutes. Add to the vegetables.
3. Combine the eggs, fish sauce and lemon juice and add to the pan and cook briefly, stirring with a spatula until lightly scrambled. Add the noodles, beef and vegetables and beansprouts. Stir fry briefly to mix everything together then serve garnished with coriander and lemon wedges on the side.