Place the Thai red curry paste, fish sauce, palm sugar, ground turmeric, coconut milk, chicken stock and fresh ginger in a medium saucepan and season with a generous pinch of salt. Whisk to combine.
Remove the skin from the chicken thighs and add the latter to the broth. Bring to a boil over medium-high heat, then reduce the heat to low, cover and simmer for 15 minutes.
Optional step: place the chicken thigh skins skin-side-down on a chopping board and scrape off any excess fat using a small, sharp knife. Arrange in a single layer on a greaseproof paper-lined baking sheet and top with greaseproof paper. Place a heavy baking sheet, roasting tin or cast iron pan on top and bake at 180°C / fan 160°C for 25 to 30 minutes, or until golden and crisp.
Back to the soup. Using tongs, fish out the chicken thighs and leave to cool for 5 minutes, then remove the meat from the bones and chop into small pieces.
Bring salted water to a boil in a small saucepan. Cook the noodles according to the package instructions, then drain and divide between serving bowls.
Add the chopped chicken, ladle the broth over the top and finish with the beansprouts, fresh coriander and chilli oil (if using) – enjoy!
