Heat the oil in a large saucepan and fry the onions for around 5-6 minutes until soft.
Add the chilli, garlic, ginger and ground spices. Fry for another minute until fragrant.
Add the turkey thigh and stir fry until the turkey has browned all over.
Add the chopped tomatoes, tomato puree, stock, lentils, salt and sugar. Give everything a good stir and bring to the boil. Taste to check seasoning, and add more chilli, salt or sugar to taste if necessary.
Reduce the heat and simmer gently, with a lid on the pan, for around 45 minutes stirring occasionally to avoid the dhansak catching at the bottom. The lentils will soak up the liquid and become thick and dark orange.
Serve the turkey dhansak with basmati rice or naan bread topped with fresh coriander if desired.