Heat the oil in a saucepan, add the onion and garlic and cook for 5 minutes until the onion is soft and starting to brown. Add the potatoes and minced lamb and cook, stirring and breaking up the mince with a wooden spoon, for 5 minutes or until the meat has browned.
Add the curry powder and cook, stirring, for 1 minute. Add the remaining ingredients and season to taste with salt and pepper. Bring to the boil, then reduce the heat, cover tightly and simmer for 20 minutes.
Remove from the heat, garnish with chopped coriander and serve with natural yogurt and steamed rice.