Southern Thai Yellow Crab Curry

1 tbsp vegetable oil 

1 x 400ml can coconut milk 

2 tbsp fish sauce 

1 tbsp palm sugar 

300g (10.5 oz) crab meat 

1 cup betel leaves, Thai basil leaves or Italian basil leaves* 

cooked vermicelli noodles, to serve 

Curry paste 

15 dried birds’ eye chillies 

2 coriander (cilantro) roots 

2 stalks lemongrass 

4cm (1.5in) piece galangal, peeled and roughly chopped 

4cm (1.5in) piece ginger, peeled and roughly chopped 

3 garlic cloves 

2 small red Asian shallots, roughly chopped 

2 makrut lime leaves, destemmed and roughly chopped 

1 tsp shrimp paste 

1 tsp ground cumin 

1 tsp ground coriander 

1 tsp sea salt 

1 tsp turmeric