Hot and sour chicken soup

Ingredients

• 500ml fresh chicken or veg stock
• Handful fresh coriander, leaves picked, stalks roughly chopped
• 1 fresh lime leaf, torn
• 3cm piece fresh ginger, sliced
• 1 red chilli, sliced
• 1 lemongrass stalk, outer leaves discarded, cut in half and bruised in a pestle and mortar
• 50g shiitake or chestnut mushrooms, sliced
• 95g cooked chicken breast, shredded with 2 forks into chunky strands
• 80g green beans, halved
• 2 tsp rice vinegar
• Finely grated zest and juice 1 lime, plus wedges to serve
• 1 tsp fish sauce
• Handful (about 10g) beansprouts, rinsed in cold water
• Fresh Thai basil leaves (or regular basil) to garnish (optional)