Spiced aubergine & coconut curry

Name: Spiced aubergine & coconut curry
Cook time: 35 min
Total time: 35 min
Cuisine: Asian, Indian
Ingredients: 3 tablespoons groundnut oil; 6 Asian round aubergines; 3cm piece of ginger; 3 cloves of garlic; 1 white onion; 2 teaspoons cumin seeds; 1 tablespoon black mustard seeds; 12 fresh curry leaves; 2 dried red chillies; 1 tablespoon tomato purée; 2 teaspoons garam masala; 1 x 400 g tin of coconut milk; 1 red onion; ½ a bunch of fresh coriander (15g)