Indian Cauliflower and Tomato Stew

5 tbsp vegetable oil or olive oil

¼ tsp mustard seeds

¼ tsp cumin seeds

2 onions, chopped

1 tsp garlic paste (peeled and crushed garlic)

1 tsp ginger paste (peeled and crushed fresh ginger)

1 tsp turmeric powder

1 tsp red chilli powder

1 tsp coriander powder

500g (18oz) cauliflower, cut into small florets

50ml (2fl oz) water

5 ripe tomatoes, peeled, deseeded and diced

lots of fresh coriander to serve