1 Combine the beef, vegetable oil and lemongrass in a bowl and set aside to marinate for 15 minutes.
2 Meanwhile make the pickled vegetables. Using a small fluted pastry cutter cut out circles of the vegetables. Combine the sugar, vinegar and salt in a bowl and stir until the sugar has dissolved completely. Add the vegetables and leave to marinate for half an hour; you can serve immediately or store for up to 24 hours.
3 Divide the salad leaves and coriander between 2 serving bowls and top with the cooked rice noodles.
4 Lightly oil a stainless steel sauté pan and set over a high heat until almost smoking. Place the meat in the pan and sear, then let it sit a bit before shaking the pan to create a little caramelisation.
5 Stir the beef to ensure it is all evenly cooked, then place the chopped garlic in the pan and sauté a little more making sure that it does not brown.
6 Keeping the heat high, deglaze the pan with beef stock or water, scraping the pan to release the caramelised juices, creating a brown sauce.
7 Throw in the beansprouts and cover for a minute, while the beansprouts cook. Add a little nuoc cham sauce and taste.
8 Spoon the beef and beansprouts with their juices into the bowls, garnish with the pickled vegetables, crispy shallots, sesame seeds and roasted peanuts.