1. Prepare the Chicken: Wash and pat the chicken pieces dry. Place them in a large bowl.
2. Marinate: Add 1 tablespoon curry powder, half the garlic, half the ginger, salt, and black pepper. Mix thoroughly, cover, and refrigerate for 30 minutes.
3. Prepare the Curry Paste: In a small bowl, combine the remaining curry powder, cumin, turmeric, coriander, and a few tablespoons of water. Mix into a smooth paste.
4. Cook the Aromatics: Heat vegetable oil in a large pot over medium heat. Add the onion and cook until softened. Add the remaining garlic and ginger and cook until fragrant.
5. Fry the Curry Paste: Add the prepared curry paste and cook for 2–3 minutes, stirring continuously. This helps develop the flavour of the spices.
6. Brown the Chicken: Add the marinated chicken pieces and stir well to coat them with the curry mixture. Cook for approximately 6–8 minutes.
7. Add Tomatoes and Potatoes: Stir in the chopped tomatoes and cubed potatoes. Cook for another 3–4 minutes.
8. Simmer: Pour in the chicken broth or water. Add the whole hot pepper if desired. Bring to a gentle boil, then reduce the heat, cover, and simmer for 25–30 minutes, stirring occasionally.
9. Check Doneness: Ensure the chicken is thoroughly cooked and the potatoes are tender. The chicken should reach an internal temperature of 74°C (165°F). Simmer uncovered briefly if you prefer a thicker sauce.
10. Finish and Serve: Add fresh cilantro and spring onion. Adjust the seasoning and serve hot with rice, roti, or dhal.