Place the chicken in a non-metallic bowl and sprinkle over the curry powder. Toss to mix well and marinate in the refrigerator for 30 minutes.
Heat the oil in a large saucepan over a medium-high heat. Add the garlic, onion and tomatoes, and fry for 3–4 minutes. Add the marinated chicken and stir-fry for 4–5 minutes.
Add the coconut milk, stock and potatoes and season to taste. Bring to the boil, reduce the heat to medium-low and simmer gently for 30–40 minutes until the chicken is tender. Serve hot with rice and pickles.