Chicken curry with potatoes, cardamom and ginger

Ingredients

• 4 chicken thighs on the bone
• 4 chicken drumsticks
• 5 tablespoons vegetable oil
• 2 medium onions, chopped
• 2 tablespoons peeled and finely chopped ginger
• 6 cardamom pods, crushed and seeds extracted
• 1 teaspoon crushed peppercorns
• 1 teaspoon chilli powder
• 1/2 teaspoon turmeric
• 6 cloves garlic, finely chopped
• small stick of cinnamon
• 2 hot red chillies, finely chopped
• 4 medium vine tomatoes, skinned and chopped
• 3/4 cup chopped coriander, plus whole coriander to garnish (garnish optional)
• 500 grams small waxy potatoes e.g. nadine (halve potatoes if they are large)
• 1 cup water