Place the stock in a large saucepan with the ginger, onion, garlic, star anise, cinnamon, sugar, fish sauce and 1L of water. Bring these ingredients to the boil and simmer over medium-low heat for 20 minutes. After this time, strain the liquid and discard the solid ingredients.

Meanwhile, cook the noodles according to the pack instructions and drain well.

To serve, divide the noodles among four bowls and top with the sliced beef. Ladle over the hot, spicy stock and then top with chilli, bean sprouts, basil, mint, coriander and a squeeze of lime.