Tamarind prawn curry

Name: Tamarind prawn curry
Prep time: 5 min
Cook time: 15 min
Total time: 20 min
Cuisine: Asian, Thai
Ingredients: 1 tbsp vegetable oil; 1 onion, chopped; 1 red chilli, finely chopped; 2 garlic cloves, crushed; 1 tbsp grated ginger; 1 tsp turmeric; 1 tsp cumin seeds; 1 tsp ground coriander; 400g can cherry tomatoes; 1-2 tbsp tamarind paste (see tip, below); 250g raw king prawns; 250g cooked basmati rice; handful of coriander leaves, to serve