Slow cooker chicken noodle soup

Name: Slow cooker chicken noodle soup
Ingredients: 20g/¾oz fresh coriander, stalks finely chopped and leaves roughly chopped; 6 chicken thighs, bone in and skinless; 1 tbsp Chinese five-spice powder; 4 tbsp soy sauce; 100g/3½oz shiitake mushrooms, trimmed and roughly torn; 20g/¾oz fresh root ginger, peeled and finely grated; 4 spring onions, finely sliced; 2 medium garlic cloves, finely grated; 2 tbsp sesame oil; 1 fresh red or green chilli, finely sliced (optional); 200g/7oz dried egg noodles; 2 small pak choi (approx. 350g/12oz), shredded into 1cm/½in wide pieces; salt and freshly ground black pepper