I've circumvented the slow-cooking of beef shin or oxtail in favour of quality store-bought master and beef stocks. I feel the shun of purists, but it means midweek magic if you are willing to overlook the shortcuts. You could give the marinated meat a flash fry to crust around the edges and heighten the lemongrass hit.
3 stalks lemongrass, bruised, white parts only, finely chopped
1 x 5cm knob ginger, peeled, chopped
1 large garlic clove, roughly chopped
1 red chilli, deseeded and roughly chopped
1 red onion, roughly chopped
350g eye fillet, very thinly sliced
500ml beef stock
700ml master stock
3 cups fresh rice noodles
2 cups bean sprouts, washed thoroughly
½ red chilli, sliced
½ cup Thai basil leaves, coarsely torn
½ cup Vietnamese mint leaves, coarsely torn
1. Add the lemongrass, ginger, garlic, chilli and red onion to a blender and blitz to combine. You still want some texture but it should be smooth enough so you're not choking on the woody lemongrass fibres.
2. Add half the lemongrass paste to a bowl with the steak and toss to coat, massaging some of the lemongrass mix into the beef slices. Set aside for 20 minutes.
3. Meanwhile, add the remaining lemongrass paste to a saucepan with the stocks and bring to the boil. Reduce the heat and simmer for 20 minutes. Strain into a clean saucepan if you like a clear broth or just leave as is and add the noodles to warm through until tender. Bring back up to a rolling boil then ladle into serving bowls. Top with the thinly sliced beef (it will begin to cook in the residual heat of the broth), sprouts, chilli and herbs and serve.