Gather the ingredients.
Start by cutting the chicken thighs into 2.5-centimeter (1 x 1-inch) sized chunks. Heat 1 tablespoon oil in a large frying pan and brown the chicken on all sides. Remove the chicken from the pan and keep to one side.
Add the remaining tablespoon of oil to the same pan, add the chopped onion and cook on medium heat until the onions are soft.
Add the green chile, ginger, and garlic and continue to cook for 1 minute, taking care not to burn. Then, add the chili powder, turmeric, garam masala, and sugar and cook for a further minute stirring constantly.
Pour in the tomatoes and coconut milk, stir well, then add the chicken and cauliflower. Simmer for 10 minutes until the cauliflower and chicken are cooked through. Add a little stock or water if the sauce gets too thick.
Check the seasoning, and add salt and/or pepper as required, then stir through the spinach until it just starts to wilt.
Serve the curry into warmed bowls with cooked rice, and/or naan bread or chapatis on the side.
