Step 1

Soak the noodles in boiling water for 5 minutes. Drain and refresh under cold water. Divide among 4 serving bowls.

Step 2

Heat the oil in a wok over medium-high heat. Add the lemongrass, ginger, garlic and chilli and stir-fry for 1 minute until fragrant. Add beef and stir for 3-4 minutes until just browned. Add the paste and stir for a further minute, then add beans and cook for 2 minutes or until tender. Remove from heat, then stir in onion, fish sauce, lime juice, sugar and herbs.

Step 3

Serve stir-fry on noodles, top with nuts and lime leaves and serve with extra lime.