Keralan prawn curry

Name: Keralan prawn curry
Prep time: 30 min
Cook time: 30 min
Total time: 1 h
Cuisine: Indian
Ingredients: 220g/7¾oz cherry tomatoes on the vine, halved; 1 green pepper, finely sliced; 1 onion, roughly sliced; 2cm/¾in fresh root ginger, peeled and grated; 2 garlic cloves, chopped; 2 tsp mustard seeds; 1 tsp freshly ground black pepper; 1 tsp ground coriander; 1 heaped tsp ground cumin; ½ tsp turmeric; 1 tsp chilli powder; few curry leaves (optional); 1 tsp sea salt, plus extra if needed; 1 tbsp vegetable oil; 400g tin coconut milk; 300–350g/10½–12oz raw king prawns; 100g/3½oz spinach, roughly chopped; 1 lime, juice only; handful fresh coriander, roughly chopped; 1 red chilli, finely chopped; 200g/7oz basmati rice, rinsed and drained well