Trim chicken - if needed - and chop into bite sized pieces. Transfer to a large Ziploc baggie, set aside.
Add the onion, green onions, garlic, scotch bonnet pepper, 1 tablespoon of the curry powder, thyme leaves, and seasonings to a food processor, blitz until roughly pureed.
Pour onion mixture over the chicken. Push most of the air out of the bag, seal and shake or gently massage to coat all the chicken in the marinade.
Allow chicken to marinate in the fridge for at least 2 hours, up to about 8 hours.
In a large pan, heat the olive oil over medium heat. Add the ginger paste and remaining 1 tablespoon curry powder, and cook - stirring constantly - until aromatic and just starting to brown. (About 1 minute).
Add the chicken - marinade and all - to the pan. Cook until chicken is browned on all sides.
Add carrot, turnips, broth, and coconut milk, stirring well to combine. Bring to a boil, then reduce heat to low. Cover and simmer for 20 minutes.
Remove the lid, stir the curry, and allow to simmer for another 15-20 minutes or so, until the gravy has thickened.
Season with salt and pepper, to taste.
Serve hot, with cauliflower rice.