Start making the curry paste, in a food processor, blend the green onions, garlic cloves, lemongrass, ginger, chilli flakes until they form a smooth paste. You can also make the curry paste in a mortar or pestle.
Bring a large pot over medium to low heat, add the oil and the blended paste. Cook, stirring frequently for 6 to 8 minutes until fragrant.
Add the curry powder and salt and continue cooking for 3 to 5 minutes until the paste starts to split and you can see an oily film separate from the paste. If needed, add one teaspoon of water to avoid burning.
At this point add the cinnamon, star anise and chicken pieces. Stir with a spoon to coat the chicken in the curry for 3 minutes. Pour the water until just cover the chicken. Cover and simmer for 10 minutes. Add turnips and simmer for another 20 to 25 minutes or until the parsnips and chicken are cooked through.
Once 25 minutes have passed, taste the curry for salt and spiciness and add coconut milk, stir quickly and let it simmer just until starts boiling.
To prepare the cauliflower rice cut the core and stems and pulse in a food processor to make small grains like rice. Place into a microwave save bowl, cover with a film, pierce with a fork and microwave for 7 minutes on high, season with salt and pepper and reserve.
Serve the curry hot with cauliflower rice.