large bunch Thai basil, leaves picked
2 red chillies, finely chopped
2 garlic cloves, crushed
1 tbsp finely grated ginger
2 lemongrass stems, split lengthways, finely chopped
1 tbsp lime juice
1½ limes, juice only
3 tbsp shredded mint leaves
4 spring onions, finely sliced
250g/9oz fine rice noodles
3 tbsp Vietnamese or Thai fish sauce (nước chấm or nam pla)
1 tbsp vegetable oil
4 tbsp roasted unsalted peanuts
2 tbsp soy sauce
400g/14oz piece fresh tuna, sliced into 4 steaks